Is our California possessed - refuses to start - control module?

Our 2008 California 2.5 TDI automatic has developed a new problem.

I press the unlock fob, car unlocks.

I open the driver’s door - hazard lights start flashing as if I tripped the alarm (no horn alarm). I close the door and open it without locking it hazard lights stop, I close it again and open it hazard lights start flashing.l

If I then turn on the ignition windscreen wipers start running at full speed. When I turn the ignition key further nothing happens the car does not start

No extra warning lights everything on the dash is as usual, just the windscreen wipers going at full speed – all as usual – glow plug symbols come on and switch off as they should as all other warning lights

If I change the windscreen wiper to interval it will do that – if on off it will –

go at full speed as long as the ignition is on



The Hazard lights can sometimes be switched off manually

Light switches, electric windows etc all work fine.

To me it looks like as if one of the control modules has had some kind of fault (water ingress?) causing currents to flow where they should not

Has anybody else experienced such a fault? Anybody know which module is responsible for hazard and wind screen wipers and where I would locate it in the van?

Thank you for your help

Yes, it is possessed!

The BCM is located below the dash to the right side of the driving column. It is a pain to reach, and it is one single module that can be replaced, but with the same version to that of your current module.

However, before you do that, I would advise you to check the earth connections (search for earth shunt on the forum) . A bad earth shunt can cause many issues. It is a fairly easy check and there is a repair guide in the VIP section.

Also check the earthing connection below the main battery.

Do the above two fairly easy checks before anything else.

kurienp said:

Yes, it is possessed!

The BCM is located below the dash to the right side of the driving column. It is a pain to reach, and it is one single module that can be replaced, but with the same version to that of your current module.

However, before you do that, I would advise you to check the earth connections (search for earth shunt on the forum) . A bad earth shunt can cause many issues. It is a fairly easy check and there is a repair guide in the VIP section.

Also check the earthing connection below the main battery.

Do the above two fairly easy checks before anything else.

Click to expand...

Thank you for your reply will check tomorrow. I will say though this has happened before. It was about six weeks ago in Venice after a thunderstorm with high humidity. After detaching the Battery and waiting for 10 minutes we managed to start it with no problems.
On this occasion again we had heavy rain and high humidity the day before. Detaching the Battery did not help though
Can I check the earth shunt without demolishing the interior?
Kind regards
Andrew

salbaderbrighton said:

Can I check the earth shunt without demolishing the interior?

Click to expand...

Andrew, yes. Refer to the document here https://vwcaliforniaclub.com/resources/earth-shunt-repair-guide.39/download

If it has happened during heavy rain/humidity, the earth shunt is a prime suspect.

kurienp said:

A bad earth shunt can cause many issues. It is a fairly easy check and there is a repair guide in the VIP section.

Click to expand...

Disagree on the earth shunt as a possible cause.

Here's the diagram https://vwcaliforniaclub.com/resources/vw-t5-wiring-diagrams.7/download

N162 is the shunt. No way I can see that it affects non-camping equipment.

yossarian said:

Disagree on the earth shunt as a possible cause.

Here's the diagram https://vwcaliforniaclub.com/resources/vw-t5-wiring-diagrams.7/download

N162 is the shunt. No way I can see that it affects non-camping equipment.

Click to expand...

Hmm. Valid point. How about the earthing point below/near the starter battery? Should check that first then?

kurienp said:

Hmm. Valid point. How about the earthing point below/near the starter battery? Should check that first then?

Click to expand...

An earth problem is plausible, I wouldn't like to venture an opinion on something I know very little about. But the earth shunt is almost certainly not the problem.

My first port of call would be an obd scan followed by trying to locate some common wiring point(s) for faults listed.

so yes have removed the fridge and checked the shunt all fine - but just to be safe applied further earth

Code reading was the first that we did - cleared them and they came back in seconds
Faults were cruise control , horn, hazard lights, windscreen wipers and a few other ones
I noticed this morning it seemed to make a difference to adjust the steering column
I then took all the plastic out to check cables. I noticed a hands-free cable that I had put in in haste and suspected it may have been pulling on the other cables
All was fine, put everything back after pulling and prodding all connections to create the previous problems - put all back together again and bang an hour later i had that possessed play station back again - windscreen wipers at full power when turning the ignition - horn going when indicating - switching cruise control off allowed the starter motor to work - At present all is good starts - runs cruise control fine indicator without a horn - but never know when it is going to come back- the plan is now to remove the control module and checking for any cracks etc.
Earthing under the battery was also checked and re-greased although looked fine

I have attached some pics of the comfort control do I have to worry about that white residue?
IO have polished most off carefully all solder points look healthy all cables and plugs were treated with contact cleaner.

Start disconnecting the systems you mention until something shows improvement.

Find the wiper motor and pull the plug. Same with the horn etc etc.

Check battery earth etc.

Cruise can be affected by brake light switch (it’s what cancels it when you touch the brakes). Check it.

Plenty to go at.