Sounds like there might be a wire issue around the clock spring if I had to guess, or some where where the horn wiring and the wiring for the steering wheel radio controls run together.
Just guessing, so don't hold it as truth, but thats where I would start. Now sure how you start to diagnose it though.
Just guessing, so don't hold it as truth, but thats where I would start. Now sure how you start to diagnose it though.