C8 Electric Doors, Windows, Sunroofs, Mirrors Failure

[housepixies109]

I've lost the use of the electric sliding doors, electric front windows, electric sunroofs and electric mirrors on my 807. The temperature sensor has also stopped working, and I can only work the electric rear windows from the rear switches. It would appear that I've lost the use of one electrical circuit. I've checked all fuses, (fuse box, dashboard, battery compartment) but can't find a problem there. I've tried disconnecting the battery for an hour, disconnecting the shunt fuse, and also the soft BSI reset procedure, all without success. 

 

Prior to the problem occurring I replaced one of the sliding door motors after the (non-electrical) cables snapped. The new motor was working fine. I also adjusted the airbag cables under the passenger and driver seat to try and get rid of an airbag fault that's been bugging me for some time. My best guess is that I've somehow disrupted a loose connection under one of the seats? No amount of wire-wiggling has put it right again though!

 

I've be very grateful for any ideas or help anyone can offer.

 

Cheers, Nick

[paul.h]

In the handbook for the C8 (available on service.citroen.com - documentation du bord - then change to English) on the fuses it also mentions the maxi fuses but does not say where they are. You might find these are in the engine fuse box and accessed by lifting the top layer of fuses if it is like the other Citroens that we have had. Possibly one of these has failed. You could also check for 12 volts at the fuses you have already found to see if the problem is before or after the fuses.

[housepixies109]

Thanks for the suggestions, Paul. I've tested all the fuses I can find, including the maxi fuses which are found in the battery compartment in the C8. None of the fuses have blown. I've got to assume that all these problems are on the same circuit and that somewhere along that circuit is a break or loose wire. Looks like it's an expensive trip to the dealership to trace the problem  :(

[housepixies109]

This problem is now solved. In case anyone else has the same issue, we got an auto-electrician in (Joe from TM Auto Electrics if you happen to be in the London area). He traced the problem to the circuit board under the dashboard, where there was a block caused by one of the connections or diodes or something like that. £200 to fix plus £45 for the initial diagnosis of the fault - all seemed reasonable enough to me. Joe was excellent, coming to my house and fixing the problem on site. As much as I would have liked to find a simple solution to the problem that I could fix myself, this really was a job for a professional auto-electrician.