FBH The end of the SAGA ?

[FrenchMike]

Originally Posted by Marky4x4

http://s1338.photobucket.com/user/Ma...tml?sort=3&o=0

Hi Mike,
I have a 2004 Landrover Freelander with a faulty FBH.
I've been directed here from a Landrover forum thread about FBH faults.
Mine seems to be doing the same as yours, the fan will run for 2minutes, then stop, wait a few seconds and it'll try to start again.
I've powered pin 3, and as said the fan runs at full speed straight away. The fuel pump cannot be heard, there is no voltage supply to it out of the pcb, if it is shorted to supply it will click, also the resistance is ok @5.6ohms.
The water pump can be heard running and the heater body gets warm suggesting the glow plug is working.
A good 12v supply feeds the heater and the earth is good too.
My pcb is slightly different from the one in your photo.
If you agree the pcb could be the issue could you check it for me please?
Regards
Mark.

Hi Mark,no prob PM sent

[Arctic]

Hi Mike.
I have removed the other PCB today and the white gloop the 4.7k & 2k resistors look ok but to an untrained eye I have sent you a PM with regards to the above, cheers Arctic.

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[Arctic]

HI Mike.
Cheers I have posted them off to you, always better to let the person whom knows to check & repair them Arctic

[Marky4x4]

Hi Mike,

PCB on its way!

Cheers

Mark.

[bmw530d]

Hello Everyone, and happy new year !
I'm from France, so sorry for my english language approximations....
I've been searching for a long long time for the "how to repear the Webasto PCB".
That's the forum ! That's the guys who know !

So, before i tell you my Webasto story, i would like to really thanks all the members of this thread fro their contributions ! They really help me in my quest of Webasto working !

So the story...
My Webasto is fitted on a BMW E39 530d, 2001MY. It was not working when i bought the car. So i've purchased, on the web, a used Webasto from a BMW car. This have worked for one year, and.... failed.
My diagnose software (inpa) said "water pump short circuit" and "water pump open circuit". Very strange, isn't it ? Sometimes, after erasing errors in the aux heater and in the IHKA, the unit begins his starting cycle, begins to warm and failed after several minutes.INPA says "water pump short circuit" "water pump open circuit". But my water pump was OK. Under 12Vcc, it was running OK, no bad bearing noise. So, it was sure it was not the pump. I started to search around the Webasto PCBs (one has never worked, and the other worked for one year).I began to search around faulty SMD resistors, transistors, like FrenchMike told us.

On the older PCB, several resistors were out ! All the resistors were under the famous F....G white paste ! I agree with you when you told this paste contains agressive agent that destroys SMD components. So this cards need some new resistors (49,9kOhm, 4,75kOhm and 10kOhm 805 size in command). Waiting for this. Note that SMD 1206 size resistors were OK...

On the latest PCB, all resistors OK, so i began to search with my multimeter in ohmmeter mode and i've found the wolf ! The positive pin from water pump connector wasn't presenting a 25kOhm resistance from the groung, like positive pin from air fan connector did... What i've found is a bad continuity on an interside hole under the electrolytic capacitor 390µF. This track is for controlling the driving current of the water pump. The hole was like corroded, this always under the white paste. So this paste didn't only corroded the SMD resistors, but also copper tracks, coppered holes of the PCB. Repairing was easy, by passing à thin wire through the hole, and soldered on both sides on cleaned tracks.
Reconnect the PCB on the Webasto in the car and it works now very well.

[bmw530d]

Hello everybody !
To complete my last post, these are some pics of the diag and the repearing of my FBH...
In these pics we can see corroded holes located just under the 390µF capacitor (desoldered for the repear)


And on the other side :


Repearing by passing a thin wire from one side to the other, and soldering on clean parts of the corresponding copper track. As you can see, the solder is not very good on corroded past...


Other side :

[Stephen Davies]

finally got one working on the bench, 47K resistor had gone bad, replaced with one of Maplin's last resistors, and its all working, very impressed with its heat output, even stuck an old central heating radiator on it, this could do a fine job of heating the workshop, now to attack the one in the car, now that i know what i'm doing

[HarryM1BYT]

Originally Posted by Stephen Davies

finally got one working on the bench, 47K resistor had gone bad, replaced with one of Maplin's last resistors, and its all working, very impressed with its heat output, even stuck an old central heating radiator on it, this could do a fine job of heating the workshop, now to attack the one in the car, now that i know what i'm doing

l

Frenchmike very kindly explained how to repair these FBH PCB's, so you can fix your own and I am sure you are not thinking of doing it - but it would be very unfair to begin repairing other's FBH PCB's.

[sln8458]

Originally Posted by Stephen Davies

finally got one working on the bench, 47K resistor had gone bad, replaced with one of Maplin's last resistors, and its all working, very impressed with its heat output, even stuck an old central heating radiator on it, this could do a fine job of heating the workshop, now to attack the one in the car, now that i know what i'm doing

These heaters are used on narrow boats for heating and hot water!
I considered using one to heat the garden room (shed )

Steven

[Stephen Davies]

When I attacked the FBH in my car found the same failures 47K resistor sort of dissolved, as mike says possibly attacked by the wrigleys chewing gum stuck all over it, I have another spare...same again but unfortunately glow pins U/S in my two spares, so the known good one went in the car, now looking for new glow pins now..not thought about fixing others but if I get the spares going at least one will be going on ebay.