I don’t know what I was getting before unfortunately, I was just pleased it was working.
Although my friend is breaking a 2001 hdi (D9 I believe but not sure, has crystal headlights etc) I was going to get the com out of it but unfortunately it has the older type controls with thin stalks, also the wiring is different there’s a plug in the centre of the airbag at the back but I put my meter on his horn and it has 12v at the wheel, maybe the older system is different?
I cleaned all 4 contact points on my wheel when changing the com, even if I pull the wire off the airbag and short it directly to earth the horn doesn’t sound..... is there anyway of bypassing this relay to check it hasn’t failed?
Bloody French electrics
Horn failure after COM 2000 repair
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- 1.8 8v
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- steve_earwig
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Re: Horn failure after COM 2000 repair
We call the earlier D9's "semi-mux", they are mux but don't have as much of the stuff as the later "full-mux" cars. One of the most obvious changes is the com2000, on the earlier cars it's just normal (not any more it aint
) 12 volt switches.
It was just a thought, unlikely I know. If that is indeed the fuse you should be able to sound the horns by giving it 12 volts.
Most of it is German...

It was just a thought, unlikely I know. If that is indeed the fuse you should be able to sound the horns by giving it 12 volts.
Most of it is German...
Unskilled meddling sin©e 2007
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Re: Horn failure after COM 2000 repair
Ok finally cracked this, the only problem was my stupidity
took the airbag off again and pulled the spade connection off the back and touched it to the earth cable (T15 torx screw) and it sounded. Amazingly when I tried before I was touching it to the centre (metal) of the steering wheel which was quite grubby.
The problem was I had cleaned the 4 contact points but had not cleaned the point where this earth connects which was not allowing the signal to complete the circuit.
Gave this point a quick rub with emery paper and rebuilt. All is now working
Steve earwig many thanks for sticking with this thread throughout my efforts, cheers

The problem was I had cleaned the 4 contact points but had not cleaned the point where this earth connects which was not allowing the signal to complete the circuit.
Gave this point a quick rub with emery paper and rebuilt. All is now working

Steve earwig many thanks for sticking with this thread throughout my efforts, cheers
- steve_earwig
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Re: Horn failure after COM 2000 repair
Yay!! \o/ Not a problem, I just didn't want to leave you in the lurch.
The steering column could even be isolated from earth, with nylon bushings and plastic joints. Anyway, just glad you got it sorted.
The steering column could even be isolated from earth, with nylon bushings and plastic joints. Anyway, just glad you got it sorted.
Unskilled meddling sin©e 2007
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- Doggy
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Re: Horn failure after COM 2000 repair
Well done gentlemen.
Good to see problems like this getting resolved, no doubt help someone else / encourage others.

Good to see problems like this getting resolved, no doubt help someone else / encourage others.
2002 HDi 2.2 Exec Estate, (2008-12) (wonderful)
2003 HDi 2.2 6-speed Exec Estate (2012-19) (also a gem)
2009 Citroen C5 2.0 HDi VTR+ Estate (godawful heap)
2008 BMW E91 330i touring (great fun - murdered by a reversing SUV)
2007 BMW E91 325i touring (slower smoother quieter)
2003 HDi 2.2 6-speed Exec Estate (2012-19) (also a gem)
2009 Citroen C5 2.0 HDi VTR+ Estate (godawful heap)
2008 BMW E91 330i touring (great fun - murdered by a reversing SUV)
2007 BMW E91 325i touring (slower smoother quieter)
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Re: Horn failure after COM 2000 repair
So does this mean this was the issue all along?
If so at least you now have a spare Comms unit
If so at least you now have a spare Comms unit

2003 2.2hdi estate - mine
1998 Volvo 940 auto estate - also mine
2019 Citroen C3 something - the wife's
PP2000 user, can help with faults / diagnostics in the Bournemouth area.
1998 Volvo 940 auto estate - also mine
2019 Citroen C3 something - the wife's
PP2000 user, can help with faults / diagnostics in the Bournemouth area.