Technical Haunted Ducato ?

[Wolram]

I am in desperate need of help! After much googling I realise that I have a rare intermittent problem for which no definitive diagnosis/solution seems to have been published.
When parked up on our driveway we were aware of a clunking noise, which turned out to be the cab doors locking and unlocking all by themselves, together with the cab lights coming on. Thinking it might be any easy fix I called out the AA. After 2 hours of head scratching their technician admitted he was flumoxed and that there was nothing in their data base.
At this point I turned the engine on and all hell broke loose. The cab doors continued to clunk, the headlights came on as did the emergency flashers, the windscreen wipers and the screen wash.
I had the van taken to our local independent truck services.
They were suspecting a fault with the Body Control Module. The BCM was removed and sent away to a specialist company for testing. They reported no faults ( phew, a new module is not cheap ). Since leaving our drive the fault had not manifested itself. The garage thought it might be a short circuit so took apart all the various multi-cable connectors, cleaned and dried them, gave a quick squirt of WD 40 and put it all back together. NO CLUNKING.
Van back on our drive, clunking starts again. Garage sends technician for a home visit. This the first time he has witnessed the behaviour and is totally mystified.
This does, however, legislate against the short circuit ( caused by rainwater ) theory as it hasn't rained since the van was originally returned to us.
So that is our current status. If you have experience of this issue please could you let us in on the secret. At the moment the van would be dangerous to drive.

 

[Greasytrucker]

If you’ve got a set of jump leads try running a temporary earth from the negative battery terminal to a solid metal part of the engine and see if it’s the same. If you’ve eliminated BCM it could be an earth fault

 

[NavNie]

Hello Wolram,

maybe your Remote Key, ore the second one in your household is the problem..
Remove the battery of your Remote Keys of the van.

Regards Klaus

 

[Anthony489]

Hi

It would help if you could reveal the age/model/type of your van.

When multiple seemingly unrelated electrical problems show up, it often means a fault in either the main common feed from the battery (i.e. before it splits up into the various circuits) or the main common earth return. Vans built from 2006 onwards (X250) have an earth return strap from engine/gearbox to body/chassis which corrodes internally and need to be replaced. Cleaning just the terminals won't fix this, the corrosion is inside the crimped ends and cannot be seen. Earlier pre-2006 vans also have their share of troubles related to their different style of earth return lead from starter to battery with a "side branch" to the body. Similar effects apply.

Do also check that any aftermarket immobiliser is working properly.

Finally, the radio frequencies used for remote central locking are close to those (legitimately) used by amateur radio operators and police etc communications. Nearby high powered transmissions can make the vehicle appear "deaf" to the remote locking keyfob, but it's conceivable that unlocking etc could occur.

 

[The Panda Nut]

It has all the signs of a loose connection / shorting. There was a post on here recently where someone was having a not disimilar issue and after a huge amount of time it was tracked to a wiring harness that had rubbed through touching a plastic part of the engine. If I can find this I will do a link. It was within the last 3 months or so I think. After soome simple repairs he was sorted. Garages however didnt help....

I cant find it. If I remember right a main loom in the engine bay was touching a platic tube amauy be intercooler ducting. Something tou wouldnt expect to cause an issue or a short. MAybe if you use the search facility you will find it.