C8 Weird horn fault

[jonkw]

Hello all,

It's been a very long time.

Have an odd problem with 2007 C8 2.0HDi. Basically, the horn goes off randomly, usually at the most inappropriate moment (!) and generally when turning the wheel. However, the horn doesn't seem to sound at any particular point in the rotation of the wheel.

I can't really offer any other clues other than it had a new Comms2000 last year, and I am guessing that the steering wheel and airbag/hornpush had to be removed for that work. However, that work was over a year ago and its been fine until this last couple of weeks. So far I have removed the upper and lower plastic cowling behind the wheel to look at the Comms 2000 and to check no wires are trapped, and have rotated the wheel with these covers off to try and get some ideas. I am guessing that the next stage would be to deactivate the airbag and remove it, and see what's going on behind there.

Any suggestions gratefully welcome.

Jon

[BenC5HDi]

Undo the battery, following the BSI reset procedure, pop the airbag off and check the connection, especially the earth at for the wheel behind the airbag. It's a common fault on Berlingos of that age and earlier.. they share the same steering wheel design.

Sent from my SM-N9005 using Tapatalk

[wheeler]

Never seen it on a C8 but seen plenty of Berlingo 2's where the Com2000 wiring chafes through on the steering column UJ & causes strange horn operation, it also normally also damages the Com2000 unit too. Worth a look as many people have fitted new Com2000 units which cure the fault for about a week until the new one gets damaged too.

[jonkw]

Thank you both for your replies. I agree that it's now out with the airbag.

The wiring to the comms2000 seems all good, I have taken the column shrouds off and the wiring there seems all ok. The Comms2000 only got replaced because the car failed the MOT due to the fact that the rear foglight wouldn't turn off (!), there were no other related faults, and, looking at my records it was done in Jan 2015. This horn fault has only just started, so thinking it's those connections behind the airbag.