FBH The end of the SAGA ?
 

MY STORY:

I came upon this Forum 3 years ago after my in tank fuel pump broke.
I found advice here to have my pump quickly and cheaply repaired.

I too also had the strange Fuel Burning Heater (FBH) behaviour caused by the K bus.
(Which I have since disconnected.)

As a regular reader, I have noted lots of threads about FBH issues and in particular
that the PCB was reported as being non repairable.

The cold days made me inclined to study the question. I began by trying to collect information about the circuit diagram etc, (not very easy)

At first I thought the Interface IC bus was the culprit.
I ordered the genuine interface IC bus (ELMOS 10026B) from Hong-Kong,
but one month later, nothing ;they forgot to ship
Meantime, I bought the Riesler interface Bus describe by Keith Alexander .
I discovered than his Interface Bus IC was a (Melexis TH3122) similar
and more easy to get.

Next, I built up a test bench and established communication between my laptop and
the Webasto PCB.
However, there was a combustion air fan error. (running at max speed).
Tracing the PCB ‘tracks’, I discovered than the power Mosfet’driver was always
ON although the Micro bus line concerned was live .The link is in fact a SMD (surface mounted) resistor well hidden under a kind of sticky sealant (looks like meringue.)
The resistor was marked 4.75 kOhms but my multimeter showed infinite !
Strange ,I had rarely seen that before in my professional live.

Anyway, I quickly replaced it and …..everything worked …..

I opened a new thread on the forums to tell the news.

So, the only possible cause, was that the resistors were being attacked by a chemical agent from that paste (meringue).

(can you imagine how many Webastos this may have affected all over the world !!)

I would like to freely publicise this valuable information, in the true spirit of the ‘Forum’ and it’s ethos of sharing information.

Most members will be able to do the work for themselves ( or know a man that can!).
However, I can do the repair for others who don’t feel like tackling the job themselves

TOOLS NEEDED:

Low power soldering iron with thin tip correctly earthed.
Table magnifier,
Solder
SM (surface mounted) resistors 4.7 Kohm ; 47Kohm


PROCEDURE

Extract the PCB from the FBH (5 screws)

Pic 1
http://rovermg1.free.fr/rovermg/thum...16KPOGQCDM.jpg
http://rovermg1.free.fr/rovermg/imag...16KPOGQCDM.jpg


Remove that sticky white paste and clean the area to show the resistors.
Take a measurement of them: two 4.75 Kohm and one 47 Kohm.


Pic2

http://rovermg1.free.fr/rovermg/thum...92bR3csgOk.jpg
http://rovermg1.free.fr/rovermg/imag...92bR3csgOk.jpg

If possible, built a test bench for checking out all the parameters before fitting on car.

Pic3

http://rovermg1.free.fr/rovermg/thum...1bfDSs8yx8.jpg
http://rovermg1.free.fr/rovermg/imag...1bfDSs8yx8.jpg

Results

Pic4

http://rovermg1.free.fr/rovermg/thum...i7LvgLmvvt.jpg
http://rovermg1.free.fr/rovermg/imag...i7LvgLmvvt.jpg

Enjoy your warmer car :):lol:

Mike

Great work Mike :D:D:D

I will look forward to having a go at the repair, mines fine at the moment (touch wood) but there's quite a few members I know that have faulty ones.

Thanks for sharing your findings.:group:



Russ

May I take this opportunity to thank French mike for all his work. I would also confirm that his 'how to 'is a genuine and 'solid ' fix for the PCB's . My own one is now working after 4yrs. of being redundant.

excellent work there - well done

need to check mine - it starts up but doesnt get hot so will to do some testing and see if i have chance this weekend to see what the fault is

So no Semiconductors failed then? Excellent Work Sir !
Hundreds of units must have been scrapped due to these resistors failing.

Amstrad products used to fail for the same reasons...................... The corrosive Glue
I used to repair Amstrad Satellites till 3 AM sometimes as they dropped like flies just after the Guarantee ended :shrug:


BTW standard 1/4 Watt resistors with legs could probably be used if there is space.
So don't worry about trying to source the exact surface mount components
They will solder on the the SM lands.;)

Frenchmike, this is fantastic news as I found my failed FBH too big as a paperweight and hopeless as an anchor, well done!

great work .....
 

:) fantastic work , people like you are a credit to this site . It just shows that things can be brought back to life , i wonder how many fbh have been scrapped when all was needed was some tlc. This is what this site is all about ....... spot on.... :)

this is a remarkable breakthrough, well done !

Excellent news Mike well done ;) thanks for sharing the info.I can see Maplins being busy soon :D:D

Groover.

Really impressive work there, well done. A definite money saver!

Can this be turned in to a pdf in the how to's section or download section? For future reference?

all i can say is "what a way to say thank you to this forum".
we have all benefited from advice on here, and i am sure we would all like to repay for the advice given for free. the job you have carried out has been an eye opener for all those with failed fbh. long may the athos of free advice continue.
could this be put in the "how to" section mods. please.

hi nick. you reading my mind?
just beat me to it.

:party:Great News I hope, as I am still unsure that this is the problem with my FBH but I am ready to give it a try.
I would like to be one of the first to give FrenchMike a little bit of business if he so desired, as I am as much use with a soildering iron as I am with knitting rubber hosepipes.
Please PM me Mike with your costings and details.
Could this be the start of something that even Webesco doesn't know about. I think we should keep quiet on this or Webesco could be buying him out!
Regards

Mike,
Well done, its always very satisfying when you get to the point of that eureka moment isn't it.

I have a little clarification for you though. I have a brand new unused 75 FBH with obligitory faulty circuit board. The SMD resistors marked at 4.71K ohms are clear to see as they are identified with numbers and both of them pass the resistance test, however the 47ohm SMD is not marked with numbers, is it ? All I can see is a Brown coloured SMD in which I get a reading of 12.8Kohms which I believe may be the faulty one that needs replacing, photo attached. This is the SMD to the right of the resistor with yellow purple and green bandings? Can you confirm?
Regards.

http://www.the75andztclub.co.uk/foru...5&d=1266053929

these faulty "resistors" do we know of a place that can supply them ???

not really in to circuit baords and the like so plenty of info is a must :)

Mike,

What an excellent how to, and this could save members £200-£300.

This meringue substance. What would be the reason for webasto putting this on?
Also, could the sm resistors be replaced with normal ones for those of us that have poor soldering skills?

Matt

Hi,Lovel

The other resistor a replaced is the one marked 4992 (49900 ohms)
I put a 47 K ohms:

http://rovermg1.free.fr/rovermg/thum...KZkls6BntI.jpg
I don't think capacitors or others components are concerned.

Mike

Hi Matt,
Another one technology fault caused by long term corrosion !

Of course,one can replace the SMD resistors by normal ones but
not necessarily more easy !

Mike

I think the sealant substance is put on by Webasto to hold the upright capacitors firmly in place. The taller capacitors could possibly 'vibrate' with all the vibrations created by road surfaces/ engine resonance etc . Could be wrong though!

My congratulations Mike on solving a long term mystery! :bowdown:

Now to the practicalities for us who have no idea what elec components are or do.. :o

I realize that quite apart from the actual FBH there are other items = fuel pump, a fan blower of some sort, elec feed to some sort of glow plug, exhaust system, etc etc that may now fail to work due to lack of use over the years..

I don't mind paying, and am willing to travel to get my FBH working, but it may need more than just repairing the circuit board.. So is anyone planning on making a comprehensive repair service available in the UK for those of us who need it please?? :shrug: :o ..
..

Ive been following this thread also as my FBH didn't work and I wanted to repair the Pcb myself as i have plenty of electronic repair experience and refused to be beaten by the lack of back up provided by Webasto .However I managed to buy a cheap unit before I had got far with researching my faulty unit so never made much progress, it s great that French mike has managed to get to the bottom of the problem and come up with a solution, my faulty unit has an earlier Pcb that is not quite the same but im now going to have another go at it and am also happy to try the repair on other peoples pcbs.As I have a spare heater I can arrange a test rig if I get a spare fuel pump from somewhere.
Has anyone got any faulty boards that I can experiment with?.
I am sure others will be able to offer a service with the info kindly provided by Mike and would not want to take work from him but am happy to provide a service if its ok with Mike.
Paul

Hi,James

Mechanical parts are rather robust !
Mine,after 3 years of non functioning, started on first time.

Mike

CPC
RS
Maplin etc

Replacement resistors don't even need to be surface mount.
The standard 1/4 Watt axial type are easier to handle & solder;)

ah i see - did look at them on the maplin site and wondered if they would do the same job - thanks !

mike
 

you know its guys like you 'and just a few others to mention' jules, big russ, raitslin' with your expertise who really get into the nitty gritty of things, that helps make this club what it is
a friendly sociable countrywide garage filled with idea's, views, know-how and advice, thats open every hour of the day and every day of the year.
what an excellent place to belong to.

a very big thankyou to you all

Second that:D And not forgetting the -Light- entertainment provided by the -sports- commitee;)

Hiya Mike. :}

>>>Mechanical parts are rather robust ! mine,after 3 years of non functioning, started on first time.<<<

Thanks for that, and I hope you are right! Dunno how long it is, or even if ever, since the FBH woorked on my car, fingers and toes crossed that it will work once the circuit board been repaired.. :o

Come to think of it, I don't know how long my fuel pumps have been in the car either so must consider replacing those as well soon. :o

Roll on spring, so I can get out and about again without freezing!! :confused: :}
..

Procedure Before Sending Your Pcb
 

PROCEDURE BEFORE SENDING YOUR PCB.

At first, manage to permanently connect a wire between pin 3 of the 6 pin plug
And earth in order to forget the +5 degrees limit.

You must hear the turbine increasing its speed and the circulating pump running

If the noise stops after 2minutes and 7 seconds, then,

The pump fuel is faulty or PCB (more likely)

If it stops after 4 minutes then the glow plug resistor is too high.
(More than 0.4 ohm)
And ignition aborts.

However, it is useful to test each component before deciding that PCB is faulty.


http://rovermg1.free.fr/rovermg/thum...FGEqtdqYxm.jpg

Since the work is easier to do than it was first time (no more IC to replace),

My PRICE is 43 £ (one hour work) postage included

Input check ,repair, and outpout control with report.

Mike

Just in the process of testing a faulty board, have found up to now 4 faulty resistors all of which have been covered in the white compound.

Both resistors below the left hand capacitor and 2 under the right hand capacitor but not the bottom 4.7K one, that one's fine. The two that have failed on the right show signs of overheating, but the two on the left look normal.

Looks like any of the components that have been covered may be suspect.

Russ

Hi,Russ

Forget overheating
Around the microprocessor,all the components work at very low power.
few milliwatts only.

Mike

fbh problem
 

I there been following this thread for a while now and i think all the info that u guys give is brilliant . i recently bought an fbh 98570B tested it the car by earthing pin3 it started its cycle then cut out i found the fuel pump was not pumping.tested the pump off the car and it seemed to work.from the info from u wise ones igathered it is the pcb:getmecoat: i have since seen another fbh for sale and i am considering buying it bmw x5 e53 will the connectors be the same and will have to 12v+to pin1 thanx

Don't think the connectors will be the same Ian

Mike can you apply your Magic out to sort the very common fault with Mk111 Satnav units. (ie LED staying on):drool4:

Satnav
 

Hi,Jules

I don't know the satnav and i haven't one but why not:

I guess they become faulty following a flood ?

You can send me one, i will have a look,one never knows.:}

Mike

No I don't mean mean flood damage unit's they are more often than not scrap.

Something corrupts the MK11/ Mk111 Flash memory/CPU if the Car Battery is removed less than 2 minutes after ignition switched off. (ie before Satnav has gone though it's shut down procedure)

Result is often that it will never shut down (LED stays on) and the PERM 12 Volts fed to it drains the Battery over 2 days (depending on Batt condition)

There you go ............a brief history.
If I send you a duff Mk111 this morning, can I collect it all repaired, this afternoon?:p:

Well,if that involves programming tools,it is much more difficult !
I am afraid not to be ready for this afternoon.:D

Is there a Kbus link problem too ?

Mike

purchased a bmw x5 thermo top the other day to use as spares to fix my fbh - the unit was off a 2005 x5 - the circuit board still has that white silicone on :(

bmw x5 fbh
 

hi there fox speed are the connections the same as the rover fbh and what is the difference between the two units?

only slight differences

4 screws hold the fan unit on (5 on older rover thermo top)
glow plug fitting and retaining clip different
circuit baord looks the same - not sure on the "programming"

connections all look the same

i swapped over combustion chambers and glow plug (after de-coking them)

works a treat now

bmw x5 fbh
 

hi there foxspeed will the whole unit work with the existing 75 wiring if u plug in the 75 connectors if no what is diffrence.also are there any compatable heaters out there which will work thanx ian:confused:

tough call mate - all the connections look the same - i would hazzard a guess the circuit board chip could be programmed differently - i didnt plug the x5 one i had straight in - i just took it apart and used it to repair mine

there are a couple of rover ones on ebay - quite cheap - was looking at those but decided on the x5 one because it was off an 2005 car and looked in good condition from the photo

the fan unit and heat exchanger look the same - so good for spares but as said its the elctronics - not sure how bmw wire theres up

sorry cant be anymore help

si.

fbh problem
 

thanx for the info foxspeed;)

Hi all i've bit the bullet and bought a soldering kit from maplins. But they don't do surface mounted resistors so my shout for help is where else can i buy them. Many thanks Stu.

Going to be doing mine this weekend, i'm going to use through hole resistors with thelegs bend underneath themselves - will do the same job. If you were being particular, break open almost any old piece of broken audio/visual equipment you may happen to have and rob one from there, they are common as muck:icon_razz:

Let us know how you get on and few photos of the finished job (for my benefit lol) would be great

Looks like the weather is stopping me getting home this weekend, looks like a job for christmas week, i'll get lots of pics if it'll help you.

PM me your address and I'll stick some in the post ( weather permitting). They come in packs of 100 and I've only got one FBH so I have a few spare!!

Also buy yourself a magnifying glass!

Could I call on your kindness also? Got a couple of through holes but would prefer to use SMD's..

A few words on SMD soldering technique might be useful....

I use a wooden cocktail stick to both remove a refit these type of components, with the point dipped in oil. With a good fixed manifying lens, so both hands are free and plenty of light. To remove, melt the solder on one terminal then push the solder out of the way with the cocktail stick - if its a two terminal device, melting the other end should then free it. Be aware that some SMD's are also glued into place, so both ends may need to be desoldered first, before trying to tease it away from the glue.

Fitting a replacement is a case of pinning the component in place with the cocktail stick (otherwise it will stick to the hot iron tip), while its ends are resoldered.

Thank You very much
PM Sent:xmas-smiley-041:

I`m not the greatest at electronic side of things, it took me 6 months to design and build a very basic circuit board at school.

so all the help is greatly appreciated

Not convinced you're much good on a PC either - you PM'd me:icon_razz:

Yep mamasboy - send me a pm and I'll get some in the post.

In addition to Harrys advice on soldering the little resistors, you may find it easier to scrape the coating off either end of the old resistor and then place the new resistor using the cocktail stick method and then solder the new resistor on top of the old one. If you haven't got a good iron this is the safest method as it lessens the risk of damaging the PCB tracks with excess heat.

One other hint is to buy some soldering paste that is designed for soldering these little b@ggers with - you just put some on either end of the new resistor, plonk it on the old one, hold it in place with the stick and add heat.

That was so you could send me a Xmas card. :xmas-smiley-041:

You've just ruined the suprise now:weihnacht2: Happy wotsit called....

MANY THANKS
Received the resistors on Monday Was a bit confused at first as to why someone would send me an empty envelope lol.

Just have to work up the courage to do it now.

Again Thank you.

Stu

Recieved mine also,sorry for the tardy thanks - wife opened the envelope and thought it was empty and threw in recycling but I retrieved them!:D

So Mamasboy, when are you away to pluck up the courage to attempt it.
Maybe we should set up a web cam and do it together ( fixing the PCB, for the dirty minded amonst us lol) :getmecoat:

Not sure about the webcam :p: but i'll possibly get to it next week and will happily video the whole thing and send it to you if that helps, i'm an ex electronic tech but dont think you'll have any probs so long as you can distinguish between the hot and cold ends of a soldering poker!!

That would be a great help,
I think I'll know which end is which when I burn myself lol.

Possible problem with other resistors
 

Hi,
I have bought a Rover 75 in the summer and now in the first cold days I tested the FBH and it was just starting up and stopping after about 2 minutes. I could hear the fan and the water pump but no clicking noise from the fuel pump. I tested the fuel pump via giving +12V on it and then I could hear the clicking noise.
I searched the net and found this thread which seems to fit my problem, thanks to FrenchMike :}.
I removed the control circuit and removed the paste from it, then found the paste black above 2 resistors and one leg of the ELMOS. It looks like burned and I could see a very small amount of black thick liquid like thing when I removed the paste.
Unfortunatelly these resistors are different ones.
One is above and a bit left from the 47K one and the other is below and a bit right from the 47K one. The first is measured to 2.56MΩ and second is 0.9Ω. Can anybody tell me if it is ok or not and what these values should be?
I also measured the resistors given by FrenchMike and the 4.7KΩ ones are ok but the 47KΩ one is measured to 37.8KΩ in my case.
It would be nice to be able to fix it.

Regards
Fegyvej
http://www.the75andztclub.co.uk/foru...8&d=1318447572

http://www.the75andztclub.co.uk/foru...9&d=1318447584

Hi Janos,

your letter box is full ...

More Heater Problems
 

Hi, just to ressurect an old thread.
I am trying to get a FBH running on an MGZT. It is a retrofit unit (if that makes any difference)
I have installed the fuel pump that is needed, and this works (checked by supplying 12V to pin 6) of the heater.
The fault is that the fan runs for about 3 seconds, then pauses for about 4 seconds, then the fan runs for about 2 mins.

I have checked the 47K Ohm, and the 4.7K Ohm resistors (the 47 K Ohm meters up at 49.8 K Ohm, so should be ok?

The other things I have checked are that, on initial start up, the glow plug gets a puse of power, but then no more power is supplied. There is no drive sent to the fuel pump.
I have tried swapping the PCB with a friend, and the problem follows the PCB (suggesting the car "services" are ok, it is the PCB that is faulty)

There is a "suspicious" looking surface finish on the item that fegyvej highlighted (in post #63), next to the 47KOhm resistor. This item looks corroded / burned. This item goes between a power pin, and pin 6(?) of the elmos device (counting clockwise from the 1/2 moon orientation marker)

Any suggestions where to look next?

Thanks
Chris

Hi,the first component is a capacitor and the second a one ohm resistor.

If you have checked all the resistors,remains the Elmos component..:shrug:

Mike

What electronic component is that?
 

Hello everyone! I have a picture with my FBH and I tested all resistors under that troublesome glued paste and everything ok, except of a green electronic piece that my multimeter read infinite. It looks like a resistor but nothing wrote on it(if it's a capacitor pls tell me what is the value). I will attach a picture with that component and pls tell me what it is(that circled and it is on pin 6 of ELMOS 10026B). Thanks in advance!

http://www.the75andztclub.co.uk/foru...4&d=1350591242

This is the answer to all the Fbh funny faults, have fixed my own car first and add the manual over ride Runs perfect. Then fitted a faulty unit to my wife's car, carried out this repair to it and away it went as well heats up perfect
Thank you very much mike u the man, Two more warm humans thanks to you

Richard and Clare Brown:bowdown:

@dj_lyw, I can't see nothing marked green you the pic you've posted, but the one in red circle is a 4k7 resistor. It was also damaged on my PCB and just replaced it.

I'd also like to say hello to everyone, it's my first post here - I've just found this forum today and it contains the largest ammount of data on fixing Webasto PCB's.

I have WEBATO Thermo TOP Z/C-D mounted in my BMW E46 but actually the board and the FBH it self is exactly the same as the one from your Rovers. In my car it only works as an aditional heater, when engine runs. However it's possible to reprogram it to work as a parking heater (using BMW INPA or BMW DIS diagnosis apps).
But in order to do that I need to make it work... Which is a problem :(

I had 2 errors in both BMW INPA and in WEBASTO ThermoTest:
1. K-bus break
2. water pump circuit break

As I wrote above I've changed the broken resistor today and the first one disapeared. So I tried to connect the water pump straight to the +12V - not working :( So I've connected P21W bulb in it's place and started the engine... It is alive!!! My happienes didn't last long - now it's getting the k-bus error randomly.

Is it possible that 10026B is damaged and works only sometimes? Is the Melexis chip plug-n-play to this board?
If car ignition is turned off the errors shows straight away, when engine is working, it's random (perhapse this are only some communication errors on the k-bus?), but still stops the FBH.
However, in BMW, ising the INPA, there is an option for FBH with 2 settings: "k-bus" or "conventional". When is set to "k-bus" - PIN1 is inactive and device only works as additional heater. When changed to "conventional" then you can start it using PIN1 so actually I could disconnect k-bus cable (and use WEBASTO cable and ThermoTest) to diagnose it. I think this should prevent the k-bus error and I could start the FBH using timer, remote or antyhing else... and it's still driven by PIN5 (thermo switch).

BTW, does anyone know if it's possible to fix the water pump? I've heard it's a brushless motor in there...

Best regards from snowy Poland (it's -2 outside and will be -20 soon so FBH is a great thing)
Greg

Hi again,

a little upadte on this one. the k-bus breakdown error comes up when the unit is suppose to start the normal heating mode. So here what happens:
- the device starts up, the air fan is working at about 90%, the glow plug is heating
- it start to pump a fuel for some time and the air fan is runing at about 20%

And this is the end, at this point the air fan stops for a momment, the ThermoTest connection breaks and after a momment it start the air fan again and the FBH status is "cooling". Also the k-bus breakdown errors comes up at this momment. When I've connected to the car via diagnosis software (BMW INPA), at the momment when the fan stops for few seconds the device status was "fan interrupt" (this I couldn't see in ThermoTest as the connection was breaking).
All the time I'm emulating the water pump with P21W bulb.

Any ideas?

I'll take the PCB out again today and recheck resistor again. Also, it happened once that the FBH started and run for a whole cycle (the water pump error is there all the time and it wasn't emulated at this time). So I adume this must be the PCB faulty. But can resistor cause this ot rahter it's the k-bus IC?

Looking forward
Greg

Hi,

Looks like a flame out to me:

Attachment 17414
http://www.the75andztclub.co.uk/foru...4&d=1351681714

And a water pump error is produced by open circuit OR short circuit.

Replace it by a bulb for test ...

Mike

Hi Mike,

yes, I'm "emluating" the pump with the bulb to even start the FBH. And, as I wrote, it's starting.
What can be a cause of "flame out"? Flame detector deffect?
And can the "flame out" error trigger the "k-bus breakdown" error?

Lot of things can produce an error;particularly for safety,the glow plug
resistor is constantly sampled;
if it falls under 0.6 ohms or so ,a burn out sequence is started...

Have a look at my diagnostics timings .

Yes, I can see that glow plug started to dropp and then the flame detecotr showed null (means that FBH stopped to burn) - this is what I can understand from that...
Unfortunatelly I'm unable to save my graphs because, as I wrote before, at the momment when it happens the "k-bus breakdown" error shows up and it's disconnecting the ThermoTest app. Also it's the only error that appears. Just came to my mind that perhapse FBH is sending it's internall error and car's diagnostic system can't understnd it so it's showing the error. I'll try to disconnect the k-bus or recode the FBH operating mode from k-bus to conventional. Perhapse then I'll be able to catch the real error or the graphs at least...
But first I'll take the control unit out again and recheck all the resistors.
Would the device even communicate with the car if the k-bus chip was broken?

Best regards
Greg

No, Search for Melexis TH3122 (same)

Ok, so if all resistors are fine, I'll change the TH3122 (only supplier I've found is Mr Resler) so by the time I'll have it, my water pump should be fixed/changed to a new one.

Then you Mike, I'll let know if any updates :)

BTW, have you been ever disassambling this water pump? It's PIERBURG and I've heared that there is brushles motor inside... BOSH pumps are having normal DC motors where you can change brushes, but I have no idea what about this one?

Sorry,i never dismantled one !
but electrically speaking it acts as a classical DC motor ...

Good luck

Mike

Hi again...

Actually I think it's built like the PC fan inside... I mean the electronics ;) But I'll let know when I'll disassable it :)

However, I heva the PCB on my desk again and from this photo:
http://lh6.ggpht.com/_iIFYxIPjiKY/TR...8122010554.JPG
source: http://www.the75andztclub.co.uk/foru...38&postcount=9
A - was fried and looks like a capacitor to me (it's between k-bus line and circuit ground so I'd say it's the k-bus filtering) and according to the TH3122 datasheet it should be 82-100pF - can anyone please confrm?
C - shows about 2 Ohm on my multimeter - can you please confirm?
Evetyhing else looks fine. I'm going to search for the capacitor and if it won't help... Then I nees to order TH3122... So few weeks to take the FHB out from the car, clean everything and fix the pump...

Thanks in advance!
Greg

Hi Mike,

according to the TH3122 datasheet (page 6, figure 8) A=100pF.
Here is the datasheet:
http://www.yeint.ru/suppliers/melexi...TH3122_004.pdf
Also there is a 10R resistor as a "protection", however in table on page 9 you can see k-bus limit Ilim=100mA. So if I'm reading it correctly then something arround 150R in the k-bus line should limit the current to little bellow 100mA. What do you think?

Best regards
Greg

Hi Greg,

Not sure it's allowed ,slew rate could be seriously disturbed .

Simplest way is disconnection !

Mike

Well, I think this would be an option:
http://www.freescale.com/files/micro...ote/AN2342.pdf
Figure 5.

Unfortunatelly disconnecting in bimma is not an option :( It's locking the device and you can't do anything with it... Can't unlock using ThermoTest so it must remain connected to the car :/

Best regards
Greg

P.S. I'm ordering the TH3122 - it's last hope to make it work...

OK,you have the BMW config,then you can without risk insert a protective
resistor of several kohms.

I guess you know how to remove the IC ..

Mike

Won't this disturb the dialog between FBH and car?

Yeap, I can handle changing the IC ;)

Thank you
Greg

Possible,begin with a high value then decrease if prob.

The main cause of killing the IC is leaving the 6 pins connector in place
WITHOUT power on the 2 pins one.

good luck.

Mike

1k would limit it to no more then 14,5 mA.

However - I've disassabled the pump and it's BLDC... Do you have an idea about type of transistor in the WEBASTO board? I'm mean the power transistors driving pumps, fan etc.? The same thing is in the pump and would need any data to see if it's working and if driving transistors are working.
I'll post some photos of it when it's cleaned better ;)

Best regards
Greg

They are very robust !

BTS 141 smart power switch

Thank you Mike :) Well, something's wrong with board in my pump - perhapse one of the driving transistors or just a cold joint - we'll see... The entire circuit is in something that looks like the PU foam so I can only clean it mechanically. Some of the elements fell of the board whil cleanig, so I'll solder it back tomorrow and check if there's something damaged. Actually only half od the circuit is broken. It happens offen in PC fans - the motor has 4 idle positions and it's starting from two of them, in 2 - it won't start...

Ok, theoretically PCB is fixed. Old IC was removed:
http://mydlarz.info/galeries/bmw/e46...er/no_chip.JPG
and the new one
http://mydlarz.info/galeries/bmw/e46...ller/chips.JPG
was soldered in place :)
http://mydlarz.info/galeries/bmw/e46...r/new_chip.JPG
You can see it covered with liquid colophony to prevent oxidation.

Haven't got time to test it yet ad my FBH is in home so I need to put it back to the car.

Also I've made a progress with water pump. I'm not sure if there's the same pump in Rover but in my BMW there is a Pierburg BLDC pump. I had to destroy the back cover on it at it was all filled with something looking like PU foam. I don't know an easy way to remove PU foam so it took me about 6 hours of machanically removing it with screwdriver and other hand tools :shrug: Few elements fell of during this process but it wasn't an issue :)
http://mydlarz.info/galeries/bmw/e46...PUMP_fixed.JPG
Ok - I've soldered those resistors back and also transistor 1 and resistor 2 were loose - looks like cold joints were an issue, just like I thought. Those BLDC's are hard to broke ;) This was also covered with colophony and will be filled with silicone to prevent humidity destroing it.

Now the pump is working just like it should and waiting to be mounted back in the car with rest of the FBH. Finally :)

Again - thank you Mike for your help and I will let know soon if the FBH is working now... should be early next week :)

Well done !

For your tests,in order to firstly rule the pump out,replace it simply by a 21w bulb....

Good luck

Mike

Hi guys

I would like to start by thanking FrenchMike for all valuable info and for sharing his knowledge:)

As of myself I am working on two Webasto heaters from E39 BMWs.

Heater 1: Combustion fan running at full speed. Have found one broken resistor on the circuit board. Will the heater work if a swap the broken resistor with a new one or might the k-bus/th3122 be broken as well?

Heater 2: Totally dead when applying power to pin 1. All the resistors on the circuit board are fine. Question, will the heater work if I swap the k-bus/Th3122 with a new one?

Anxious for an answer.

//Andreas in Sweden

Hi and welcome,
I assume that after some time it just stops? Can you hear water pump or fuel pump runing as well? Tehere's no answer to your question - you need to replace the faulty element, put the control unit back in to the FBH and test it. If it works then you're fine. If no - well, you know what to do.
Ok, this is the interesting part. You need to know then in bimmas the FBH had two options:
1. additionl heater - supporting engine heat up when started cold (bellow 7*C outside)
2. parking heater - able to run when engine is turned off.

If your's was installed as option #1 then it won't respond to voltage on PIN1. You need to recode it (with BMW DIS - it's the easiest way).

In E46 the parking heater was driven by auxiliary clock (the small thing with display and WEBASTO logo on it). But AFAIK in E39 it was controlled by MID or instrument cluster if you had the full OBC.

Best regards
Greg

Quote:
Originally Posted by Onepinshort http://www.the75andztclub.co.uk/foru...s/viewpost.gif
Heater 1: Combustion fan running at full speed. Have found one broken resistor on the circuit board. Will the heater work if a swap the broken resistor with a new one or might the k-bus/th3122 be broken as well?

I assume that after some time it just stops? Can you hear water pump or fuel pump runing as well? Tehere's no answer to your question - you need to replace the faulty element, put the control unit back in to the FBH and test it. If it works then you're fine. If no - well, you know what to do.

Quote:
Originally Posted by Onepinshort http://www.the75andztclub.co.uk/foru...s/viewpost.gif
Heater 2: Totally dead when applying power to pin 1. All the resistors on the circuit board are fine. Question, will the heater work if I swap the k-bus/Th3122 with a new one?

Anxious for an answer.

//Andreas in Sweden

Ok, this is the interesting part. You need to know then in bimmas the FBH had two options:
1. additionl heater - supporting engine heat up when started cold (bellow 7*C outside)
2. parking heater - able to run when engine is turned off.

If your's was installed as option #1 then it won't respond to voltage on PIN1. You need to recode it (with BMW DIS - it's the easiest way).

In E46 the parking heater was driven by auxiliary clock (the small thing with display and WEBASTO logo on it). But AFAIK in E39 it was controlled by MID or instrument cluster if you had the full OBC.

Best regards
Greg

Hi and thanks for a fast answer Greg. I have the additional heater in my car.

In this case it won't work if you apply 12V on PIN1. You need to recode the FBH. You can do it using DIS or NCS expert. You'll find a lot of "how to's" on the internet. In the BMW the FBH is driven by k-bus. Also computer diagnostic would be good idea. You can build the webasto interfce (I've posted a link to a very simple interface earlier in this topic) and the webasto thermotest app is free to donwload from webasto web page.

Best regards
Greg

Hello,

Sorry, that I'm only a BMW driver but it seems that this thread is the best in Webasto repairing.
So: I have Thermotop C in my E61 diesel (original from factory so replacing pcb is not available as a spare part) and I have figured out that the problem is in fuel pump circuit (analysing s/w says the same). Ok, possible other fails also, but let's start from this.
The pump itself clicks when powered directly 12v an actually I managed once hear steady clicking form under my car, and a couple of times one or two licks. naturally the unit locks itself after three attemps, but fortunately I have BMW DIS analysinf s/w to unlock it.
I put multimeter to pump socket (near to pump) and started the unit with remote control. Voltage rose from 0 to 0,78 V and it looks like its ticking (I have analog display as well).
My conclusion: fuel pump electronic circuit is broken, and I guess it is the end stage (read fet or transistor). Am I in the right direction? And any idea what component (and type) it is is inte circuit board?
Im an electrical engineer and soldering iron is quite familiar tool to me :}

Hi,

Voltmeter is useless;put a scope on pin 6 and you'll see positives pulses
40 ms wide at a rate of 1 to 2.3 per sec.
In case of no pulse,there are lots of cause possible to prevent feeding fuel
(for safety reasons).
The end stages Mospower are very robust ..check resistors firstly..:}

Mike

Thank's for fast reply. Ok, the pulse width is so narrow. I still think my high quality multimeter should have indicated this with it's analog bar, but not sure anymore. Unfortunately I don't have scope in my hand, thinking to buy one. I will once more come back to pump itself and test it with "manual" pulsing. If it still clicks, then I remove and look at the pcb. resistors does not sound very easy to replace.
If I don't see anything clear what is burn/broken I will rise my hands up. Fortunately we have here in Finland also a repair shop special for these Webasto pcb's from BMW and others.
I will report when I have studied a bit more.

Ok, I give up, I surrender :mad:
I removed PCB, I couldn't find anything suspicious there, measured every resistor (I think) and those seemed to be ok.
I studied a bit fuel pump circuit and it seems that pump is driven by one IC with 8 legs and it is soldered also from its body to board. I cheked that +12V circuit is ok to chip and signal from chip to pin 6 in X1 is ok also. I cannot do anything more.
Frenchmike, still repairing these? Aprog delivery time today?

No answer, so my one man talking continues...:)
The chip is actually 10 leg VND05BSP monolitic dual channel switch from SGS Thomson. One channel is only used.

I'm not sure, but if I understood correctly the chip schematic, it will jump from 0 to 12V when input roses from 1,5V or less to 3,5V or more. So, when in my case, output voltage is about steady 0,8V when switched on, I'm quite positive that this chip is the guilty. I'm I right?

Best way would be building a diagnostic cable. You'll have the answer. I think you've mentioned you have a BMW cable and DIS. Is it showing any errors? AFAIK the fuell pump is only driven by short +12V pulses. If it's not clicking, when FBH starts it can also mean any FBH error that prevents the device to start. I had my water pump broken and the melexis chip broken too. I never heared of any issues with fuell pump control. The pump itself is available and not very expensive too. I think that you should be able to find the fuell pump pinout on the internet and try to apply +12V manually to it's pin. It's driven from the pin6 of X1 conenctor in the FBH PCB.

Best regards
Greg

Yes, I can read and control FBH no problem with my s/w. Actually there have been several issues (discussed with specialists) about pump control in E6X BMW cars.
As written earlier, only error it gives is "fuel pump circuit open". I read VND05BSP manual, and it has diagnostic pin which, I assume it used in Webasto also. It is quite stupid and give only very basic type error situations.
When its gives that previous mentioned error message, there are actually few possibilities:
1. pump circuit really is open (not in my case, all the cables and pump are ok)
2. the chip is partially dead but manages to send this circuit message to main cpu
3. chip is totally dead and main cpu assumes that fuel circuit is open.

But, remember that when I start FBH, I can read small voltage from pump connector, meaning that this chip cannot be totally dead! When Webasto is shut down, this small voltage drops to 0.
Please read ALL of my previous posts.
Unfortunately none told me (or they didn't know) resolutions for those.
In E60 the fuel pump seems to be quite rigid, and so mine is clicking as it should be. You can manually test it, but not run (read, 40 ms pulses in 1 to 2 Hz)

Actually I allready did some time ago. Unfortunately, my model is new to him. But: as soon I get better from my flu, I install my modificated pcb, and test it. If it does not work, I change the chip and if it is still without pump current, I will give it to local expert (they have huge repair queue presently). Our cold days will last about one month still, so I should repair it relatively quick or it does not matter anymore for this winter :}

Edit: I swapped output to an other FET port in that circuit. Didn't help. Cuircuitry worked exatrly in a same way than before (so, I didn't break anything extra ;) )Ok, it was too difficult job to me and my tools anyway (too small connections). So it is possible that my connection was wrong soldered. I ordered new chip and will have it in a couple of days. Local electronic shop can do the swapping without a problem. I will then once again check all the cables & connections, put everything together...and hope the best. If it does not work, I will give it to expert.

jaki, if you'll apply a lot of flux or colophony then solder will hold to the copper and "get away" it self from the laminate.

Best regards
Greg

In the absence of a 'scope, a logic probe with a cmos setting would pick up and show the pulses.

A big thanks to Frenchmike for fixing 2 pcb's for me.Both FBH's are now running well.The man is a genius :)

Good for You, I even swapped (or electronic shop did it) new output stage for fuel pump, but result was same than before. I cheked fuel pump cabeling once again but everything was ok.
I found from motor-talk a couple gus with similar eerror codes. No answer there either :(
I give it up. I will visit an expert when I hve little more time.

Sad story to my Webasto.
I had problem with my battery (original from year 2004), and there was also litlle contact problems with battery cabling.
I managed fire my car with jump start and bought new battery. Everything else is ok, except this FBH. First: I couldn't get contact to it with my DIS. Then I realise that its fuse was blown. I replaced it and the I heard aux water pump running on all the time. Ahd: this is serious: I couln't still get any contact to it :( Even when car totally switched off water pump remains on, meaning I was forced t oremove that fuse.
So my unit seems to be very sick.

Hi Mike,

Any idea which component causes the error message "Glowpin flame sense interrupted- Short circuit". I found one 4.7K resistor open circuit, but the error is still there. The glowpin is not short circuit because i tested it in another heater.

Hi,

The quickest way is checking all the resistors...

It was a solder joint this time. It seems the chewing gum has attacked the joints on the resistors which was very confusing because when measuring the resistors on the top of their caps they read fine, but when I scraped away the varnish on the pads and measured there, they read open circuit. Ended up replacing 2 x 4.7K resistors and 1 x 10K one.


That chewing gum has a lot to answer for.

Yes,chewing gum + temperature :shrug:

I would like to offer my sincerest thanks & gratitude to FRENCHMIKE for sharing his knowledge on fixing the Webasto. I have a BMW X5 & as a result of following his diagnosis & repair procedure I successfully repaired mine today.

Well done FRENCHMIKE & a big round of applause to you! Thank you so much.

Very happy for you Steve and glad saving
all these condamned webasto's...:xmas-smiley-032:

Mike

Bmw e53 fbh
 

Mike,

I have a 2005 E53 with a erratic running combustion fan motor. It will start OK run for about 2 minutes then run erratically & shut down with INPA message Fan interruption. Have read about faulty 4.7k resistors in PCB but could it be clogged combustion chamber causing flame out? Can you repair BMW PCD's. I am capable of changing resistors but don't want to start until sure that fault is PCB?

Would appreciate your thoughts

Mark A

Hi Mark,

You have to know that i can't test entirely the BMW one's for the cycle is
depending on the Kbus 'car.

I only can test the driving of the external components .and read the recorded
errors.

The Rover's are more easy to test ..

However,i can still have a look :}

Mike

fbh
 

my fbh wont fire up it runs but doesnt fire is it the pcb i would like french mike to have a look at it have anyone got a contact address for him ,or can mike please contact me himself,i would be apreciated for any help

just click on his name and send him a PM....

Mike,

Do you still do PCB repairs?

Hi, and happy new year to everyone. My first post after being a member for ages, apart from P.Ming big russ and having him remap 2 ecu's. I don't really want to impose on the good people here, but I feel I need some answers from the boffins here! I have ploughed through endless threads and posts, but just got mesmerised, so I hope it's ok to post here!

I have a unhealthy obsession with fbh's, especially after reading the endless information on this site about them, and past experience with cab heaters in my trucks!
I have one already fitted to my saloon, but I bought one complete with pump, and retro- fitted it to my 52 plate tourer.
As soon as I put fuse 8 in, the fan motor burst into life and ran a few seconds. I couldn't get it to run at all after that, it was dead, tried resetting it by removing the fuse, but still nothing on earthing pin 6. I replaced the fuse a day or so later and it fired up and ran! I was a happy chappy! However, after a week it just started running the fan and the water pump, but it just wouldn't fire. I tried resetting again, but nothing.
I have a perfectly good one, which I know works on my 75 saloon, swapped them round, it did the same thing when connecting the battery to the saloon, only this time it burst into life, only to cut out and just run the fan, blowing cold air out of the exhaust and circulating water. Fired up the known good one on the tourer (originally off the saloon) and it worked perfectly!!..... For a week.... Now, Monday, that one has started the same game!! Although, this one doesn't start running on connecting the fuse, symptoms are the same, i.e. running the fan (a little faster than usual) and water pump, but not firing!I also bought 2 gsm's off ebay after reading all about them on here, but they aren't without their faults either!! one doesn't quite work as it should, although, i have no instructions apart from what's on the listing and what i can squeeze out of the guy by asking! and the other didn't work at all!!!!I also fitted the maplin relay on the heater
too, as done by another excellent life-saving-member, it was lovely while i had it all working "to a fashion"! Now, someone mentioned that they aren't very good as anchors or doorstops, but I'm liking the idea of donning my steel toe cap boots and launching them like rugby balls, or, a splash of petrol and a match to activate them....I hope the other genius aka FrenchMike reads this, because, surely it would be an unlikely coincidence that both pcb's fail, and in the same way in such a short time? unless it's something that is blowing the resistors, but there's only the 5c temp wire, dosing pump and pin 6 earth activator fitted, the k-bus is disconnected.On another note, i removed the first pcb, cleaned off the gum around the capacitors and found the furthest right one was black on where it had sat on the resistors I also took out the pcb for the other fbh, but surprisingly, this one is almost charred under the blob of gum,on the right of the pcb. Now, another God "HarryM1BYT" shows a picture of a different resistor marked as one of the" failers" to what FrenchMike shows in his picture, unless I'm looking at it wrong, but does anyone know what type the other resistors are and what size they are in that area on the board, under the blob? and what particular size they are, ohm, wattage and physical size etc, or doesn't it matter? if a reading can't be found with a multimeter (i just bought a new one, and both my old one and new one don't show any readings, as if they are open circuit, so how do we know what to replace them with?! i'm not a big electrical wizzard, in fact i've never tackled anything as small and fiddly as these resistors) I've just ordered a table magnifier in the hope of doing these myself....
Even "if", by some miracle I get them fixed, I'll still be worried about putting it back on the car in case it blows again!
I've attached a couple of pictures of the bought pcb (first one to snuff it) which seems to show one of the offending resistors looking suspect and the pcb from the known good one (well, was a good one...) Showing the charred area around the right hand capacitor where the gum was.
Any pointers and/ or ideas would be gratefully received.

Thank you very much!
Paul

http://www.the75andztclub.co.uk/foru...6&d=1420692365
http://www.the75andztclub.co.uk/foru...7&d=1420692397

Thanks for that Mike, much appreciated.
Yes, silly me, I meant to say pin 3 of the 6pin plug, I use this to activate it via the gsm.
I wouldn't think there would be anything wrong with the fan, pump and glowpin, as it would be a coincidence to have the same fault on two different burners, but of course it can't be ruled out, I would suspect the fuel pump wiring, but not too sure how to check it. The batteries on both cars are very healthy, showing over 12.5 volts.
I'll try your test when I get chance, thank you for that.
What would you advise on resistors there, as they look pretty fried on the second pcb?
Thank you very much.

Paul

To test the external components ,You have all the infos on my schematic

And Forget the color of the resistors .the ohmmeter is the only way.


Mike

Thank you once again Mike! I'll do the tests at the weekend or before if I get chance.

Paul

Hello comunity, big thanks to French Mike and the passion he shows for these cars and to everyone that contributes to this forum, it's my second week here and i already found cheap solution to 2 of my problems, (how to get a cheap MAF sensor thanks to HarryM1BYT , and this one with the damaged pcb which eventually i will get it done)

I have the old version of the Webasto on my car which is 66232C, i tested with +12V to pin 1 and the machine starts for 2 minutes and then gone. I haven't tested the external components but i heard the air fan running for the 2 minutes it did and i check the hose that goes in the engine while working and there was some action going on, nothing to say about the fuel pump...btw does the schematic you Mike drawn for testing external components is valid for the old Webasto also? And one more the order to remove the 2 wires connected to Webasto is 1st 6-pin plug and then 2-pin plug, and to reconnect you need first to connect the 2-pin wires and after the 6 plug am i right?

One thing i haven't done is to remove the pcb (i don't remember where the instructions threat is) , i did some pictures to it as it is and eventually i'll remove it and find someone capable of doing the job around here as i'm from Bucharest(Romania)


I need to find a way to test the plug and the fuel pump beside getting done the pcb and also please teach me to say thanks to users

All the best
Alex :new_year:

http://www.the75andztclub.co.uk/foru...6&d=1421191039.
http://www.the75andztclub.co.uk/foru...7&d=1421191056

http://www.the75andztclub.co.uk/foru...8&d=1421191088

http://www.the75andztclub.co.uk/foru...9&d=1421191106.
http://www.the75andztclub.co.uk/foru...0&d=1421191123

Hi Alex,

On your type (first one) no kbus is fitted ,so no worry about the disconnecting
plug order ..
The schematic is the same except the auxiliary command.
(you have to connect pin3 to +12v )

This model is more robust than the other ,then faults vicious to find out .

Is the 5 volt generated ?

Mike

Hello Mike,

So the scheme from post 121 you drawn remains the same except connecting +12v to pin3, not ground to pin3 as for the newer model, correct?

(sorry my knowledge of the machine is a bit poor) how can i measure if the 5v is on? (i have a metter for that)

Can it be possible to fix it or it's a waste of time?
My car is going to 9 o'clock temp indicator in about 20 minutes more or less depending on the driving style, do you think the thermostat has something to do with that?

Kindly thanks for getting envolved

Alex

Hi Alex,

To read more accurately your engine temp,use the OBD in 7.0

http://www.the75andztclub.co.uk/foru...rd+diagnostics

You have a PM

Mike

Ok, I've been quite ill, so I only just got chance to do your tests Mike.
I took the worst pcb, the one that looked like the elmos was burned and experimented with it, it started giving me readings from all the resistors, so i re-soldered them, put it back in the car and it works again!
Now, while I was at it, I did your tests as per your schematic. On the water pump, the bulb lit, but not as bright as if going direct to the battery, and the pump made a noise, moving on, the combustion fan ran while the bulb was lit "half brightness" and the fuel pump lit up too, also not as bright. Does this sound ok?
The other boards have dead resistors on them, so I will change them and see what happens with them, although I'm not sure about the physical size of the smd resistors, I got 4k7 and 47k, the body size is 1206, but seems a little too big, would 0805 be better? and what wattage should they be, 0.25w or 0.1w?
Thank you!

Paul

Yes Paul,everything is normal unless it will stop :}

http://rovermg1.free.fr/rovermg/imag...WEgsi5xwo7.jpg


http://rovermg1.free.fr/rovermg/thum...WEgsi5xwo7.jpg

And most of the resistors are 0805 /0.25 w

Mike

Paul
Just a thought, the fuel pump is solenoid driven (it has a pulse signal) so the light should 'flash' in sync with the pump.
As mentioned in Mikes post #121
I think you could have a fuel pump issue, hence why both FBH's have issues when fitted to the car.

SteveN

The easy way to know whether the pump is working, is to listen to it for clicks. The speed of the clicks vary, depending on the combustion state of the FBH, but they are easily heard. If its clicking you can be 99% sure it is pumping, but that doesn't guarantee fuel is coming out.

Yes Harry and if fuel refuses to come ,a flame out error is generated and
the burner stops ...

:new_year:

Mike

Hi Steve,
Thanks for that, I was actually doing the light bulb test with the unit inactive, I wasn't 100% sure whether I was supposed to do it that way or not. However, after fiddling about with the pcb, I got it working again, and it's working now, although I've cut the wire from the temp sensor, so I only use it as a parking heater. I was concerned too about a pump issue, but I wondered if the wiring was shorting somewhere, as the previously mentioned pcb was very black, making me think it was completely shot because of a short or something, especially when the unit before stopped working too, and seeing that the only things wired externally of the fbh's, are the temp sender and the pump, or maybe it was a coincidence both units died?


Yes Harry, the pump is working, its clicking as the fbh wants it to, slowly at the start and getting faster as the fbh gets up to full speed and maintaining it until its switched off. When the car ate the burners, I tested the pump directly via the terminals, and it clicked as it should.


Thanks very much to everyone, especially Mike!

Fiddling about with it and it starting to work, might suggest it went into lockout....

If it tries to start three times in succession and fails to get ignition, it goes to lockout. It then remains locked out, until reset. You reset it by pulling the fuse or power plug, out briefly.

Yes, that was the problem to start with Harry, I thought it was in lockout and reset it so many times that I lost count. The other unit would start running as soon as power was applied, well, the fan started running at high speed for about a minute then stop, putting, grounding pin 3 would start the fan at high speed again along with the water punp, and stop after a couple of minutes. As you say, three times and it went into lockout, so I would reset, and the whole process would start again. K bus is disconnected. I traced back to problematic 4k7 resistor on that particular pcb.

Hi Guys,
Hope you don't mid my asking, my 2005 year MG fbh hasn't worked since 2012. I dekoked it last week. The air fan was stuck and full of debris, and now it works if i give it 12v on pin 1, and successfully heats up the engine. Left to its own devices, nothing happens. The car's harness gives no signal on pin 1 regardless of the outside temp. Where should I look next please?
Mike.

If the unit is not starting at the correct temperature suspect faulty temp sensor, or wiring.

See 2nd and 3rd links in my signature.

Be aware if you need to change the temp sensor and you use the land rover ( L ) coded one from Rimmers, it will trigger the FBH at approx +10 deg or less, as opposed to the Rover oem one at +5deg or less.

Snagger.

Run signal is produced by the alternator being driven, it then goes to a thermostat behind the front bumper, set to close at or around +5C. So engine running and outdoor temperature needs to be below +5C before the FBH will run automatically.

Check my FBH Help by clicking the link below....

Spike, if you don't mind me asking - did you "just" remove the top cover to sort the fan out?

Kev

Many thanks Snagger and Harry. I'll go looking this weekend.
Kev, no, I stripped the whole shebang to dekoke it because I didn't know what I would find after a few years of inactivity. I couldn't see how the fan impellor came off, so I blew through the fan with compressed air, then ran it on 12v for a while shaking it to clear any dirt inside.
Thanks again,
Mike.

Thank you Mike for all your job you do here!

I am a newbie on this forum – found it recently. Thanks to this great discussion I could have discovered the same resistor problems on my Webasto PCB as well.

My Webasto had four problem resistors on the microprocessor side and one problem resistor on the flip side!

The Webasto however does not work yet. By mistake I have damaged part near processor and now I do not know what part is was.

Could someone possibly let me know the code marking which has been written on the part? I would try to replace it first and then carry on testing.

http://www.the75andztclub.co.uk/foru...1&d=1423214604

Thanks a lot Martin

Hi Martin,

4751=4.75 kohm can be replaced by 4.7k (4701)
4992=49.9 kohm can be replaced by 47k (4702)

Good luck

Mike

Oh Mike, thanks a lot!
I am sorry. I was not very clear with my question. There is a part in the yellow square. See the new picture attached. It is a transistor, diode or some other part. I have damaged this part by mistake. Now I need to replace it.
Cay you look at the PCB if you can or someone else and read the the code which is written on the part so I can decode and substitute it?
http://www.the75andztclub.co.uk/foru...0&d=1423236162


Thanks a lot!
Martin

Something like "JE" if it can help :duh:

Hi

On my board its a A7w transistor, but my board is of a BMW so poss not the same.

Thanks vpug

Hi Mike

I take it the IC's never got to you then, did you get any more yourself.

Thanks vpug

Hi,

3 weeks ago i have send an order to the link you gave me ...
and on 26 of january i have received a message:

"Your Order has been shipped"

So fingers crossed :shrug:

Is your burner working ?

Mike

Hi Mike,sent you a private email
Regards Pete

Hi Mike

Was that just the standard free post then not dhl like the one that I sent for ?
Last time they came in a week saying that the snail mail never got to you.
I never got the bmw webasto running as I pickup a c8 one and now have fitted that.

Thanks vpug

Yes,standard free post (no hurry)

I hope you know the BMW one doesn't run on the Rover 's ?

Can anybody help,i have a late Mk 2 cdti tourer with no fbh fitted,i have been offered one from a 2003 mk 1 saloon which is still fitted to the car,firstly are they interchangeable i no i need the complete unit and fuel pump is there anything else i need from the donor car.
Thanks Pete