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Hah! Horn problem solved. Its pretty elusive:

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Normal car, not track car. 04 base.

I'll find the horn and check connections. Hate removing the steering wheel, but I guess that's next.


Grant gee-lenahan-at-vee-eff-email-dot-net
No Bentley manual to refer to or I'd check before posting but I'd check what fuse the horn circuit is on and see what other things might be on that circuit too and see if they work.

Next check the electrical connections at the horn(s).

Does the steering wheel have any other buttons/controls that have to work through the wheel/column interface? If yes do these all work?
The horn is activated by the metal plate behind the airbag making contact with the steering wheel. You can access both sides of that connection by removing the airbag (4 torx screws that face the front of the car). If you have taken off the wheel before then maybe the ground wire behind the airbag wasn't securely plugged in.

I would start by checking the fuse, though I suspect you already did that.

Grant gee-lenahan-at-vee-eff-email-dot-net
Its suddenly working plain and simple, with nothing done.

So its either:

A) a logic fault that somehow closed an accessory relay, or
cool smiley the garsh-darn ignition switch not connecting some accessory power (a common problem in older Audis with the same switch)

Time will tell.

Solution: "control-alt-delete", sorta.


Grant gee-lenahan-at-vee-eff-email-dot-net
There's no logic
Boxsterra - 2 years ago
And the ignition switch isn't involved.

Power circuit
Battery → Fuse → Relay → Horns

Logic circuit
Relay → Steering wheel contacts → Ground

Common causes are:
- Blown fuse (check fuse)
- Bad relay (swap relay)
- Bad horns (usually go one at a time)

Less likely but possible if you've done service in these areas:
- Bad ground wire connection in steering wheel behind airbag
- White X1/1 connector (located behind carpet in front trunk on the left side) not seated properly
I've seen this before on Audis. Switch cuts all accessory power. Are you saying horn is not on that main circuit?


Grant gee-lenahan-at-vee-eff-email-dot-net
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