Rotary coupler behing the steering wheel. Be very careful if you're considereing doing it yourself as it involves removing the airbag!
Rachel
February 2011
Don't want to be silly but have you checked that the actual "horn" works. If not check it with some wire connected to battery. If you are not confident enough to do this leave it for some one else..
rayt
May 2010
I have the exact same problem with same model Volvo. Car is great and reliable, but since last year, n horn.. illegal for one thing .. MOT is looming... it would be a shame to condemn a good car for the sake of a horn fault. Let me know if you get any answers.. I haven't yet and asked 2 months ago.
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