WEBASTO FBH DIAGNOSTICS update

[James.uk]

Ellow Steve.

I got the remote kit by 2nd post today, thank you very much!

Now I need to find someone to wire it up. The good news is, i have found a local car electrician who by repute is very very good at radio and remote stuff, so I will pay him a visit asap.

Thanks again Steve.. I will post again here when I have been to the elec bloke..

PS. No bangs yesterday, coz it's too warm here now at 10c ..
...

[Mintee]

FrenchMike, I have a Webasto but I don't have a fuse in F8 (engine bay fusebox). I have a feeling that this has been removed for a good reason.

Is this likely to be a fixable fault?

[FrenchMike]

Originally Posted by Mintee

FrenchMike, I have a Webasto but I don't have a fuse in F8 (engine bay fusebox). I have a feeling that this has been removed for a good reason.

Is this likely to be a fixable fault?

Yes,i guess there is 99 out of 100 that your PCB is faulty !

If you want your car warm quicker send it to me.

Like James did last week..

If interested in ,send me a PM for details

Mike

[James.uk]

My FBH worked again this morning! YAYYY..

Now I need to get the remote that "Starman" sent me working and I will be warm n toasty every day..

As Mike says, 99% of the time the fault is on the lil PCB..

Erm, mine still fires up with a muffled BANG but at least it lets me known it's on!
...

[Mintee]

Well.... Yesterday I Googled to check how to remove the Webasto PCB and came across this thread. In it FrenchMike explains clearly what is likely to have failed on the PCB and what needs to be replaced.

Originally Posted by FrenchMike

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

Since I knew there was a good private TV repair man nearby I gave him a call and he was willing to have a look at it.

I took it over and he had a look at the website, then the PCB, removed the paste and showed me two dead resistors, had a ponder made me a cup of tea and set about replacing them with ones that (I think) are the same resistance but higher voltage (? - I have to confess most of what he was telling me was going over my head!) as they will be less likely to blow. He did say there were detail differences between the board French Mike had posted any mine but the resistors were basically the same. One of the three FrenchMike had identified had not blown but my chap said it was a higher specification (higher voltage ?) than the others that had blown so he left that rather than replace for no reason.

Anyhow, picture below of the board after repair for those that know about these things.



My chap did wonder why that chewing gum paste was there. It might have been a dodge to try to stop the resistors blowing but a properly designed system should not need it so he put some glue from a glue gun on the capacitors 'in case that paste was there to stop vibration fractures' and charged me £40 for the job. Took less than 45 minuets and I got a cup of tea!

I stuck the PCB back in this morning and put a 15A fuse back in slot 8 and the fan does not fire up when I open the door.

Too warm today to see if it fires up when cold. I guess I should do the pin3 test and see if it runs......?

[Mintee]

Originally Posted by Mintee

I guess I should do the pin3 test and see if it runs......?

Err..... which is 'pin 3'?

Unless my eyesight has deteriorated more than I think there is nothing to identify it on the plug. I presume that it is one of these..... as the other connector on the Webasto only has 2 wires going to to it.


(Sorry about the rubbish phone camera picture)

If I do a search for 'pin 3' and all find is people discussing 'pin 3' and no details as to which one it is.

[r44flyer]

Where are you Mintee?

[STUBIE]

It's the bottom left as you look at it.

Stubs

[Mintee]

Originally Posted by STUBIE

It's the bottom left as you look at it.

Bottom left of my picture? The brown and white wire?

How the hell did that get identified as 'pin 3'?

Ok I'll go an earth that. If nothing happens I'll stick it on the positive terminal of the battery. That should give it 12v, yes?

[Mintee]

Originally Posted by Mintee

Ok I'll go an earth that. If nothing happens I'll stick it on the positive terminal of the battery. That should give it 12v, yes?

It wasn't that one! For future reference the plug is numbered but only visible once it is unplugged! So, as I think STUBIE was suggesting, it is the one (in my picture) beneth the two wires on the block

1 4
2 5
3 6

I have wires in 1,2 & 6.

If you see what I mean

Anyway, I did the test this morning with the car cold. (1.5º air temp and 2º engine unstarted on dash OBD) Earthed the wire against the battery earth and the Webasto fan ran up. I wasn't really ready with my phone stopwatch but it seemed to run the fan fast and slow before giving up after about 5 minuets.

I was a bit disappointed as I thought I could smell diesel but the exhaust was not hot. Bah! I thought I'd best try again and get an accurate time as it was looking like the ignition fault.

But this time it fired up! Fan run, some smoke from the exhaust, clicks and creaks as the cold metal warmed and I could feel 'warmth' from the exhaust on my ankles as I stood there. I gave up after 6m30s as my finger was getting cold holding the wire to the battery terminal. I checked the OBD and engine temp was already 33º. Fired up the motor and warm air came out of the heater! (The OBD dropped to 27º/28º though!). Success!

Have to see how it works in use. It didn't seem to fire up again when I started the engine for a couple of minuets - but it might have thought things were warm enough by then?