Today I was in the garage again. Unfortunaltely the horn push was not the main problem.
One positive thing was that I now have some strong indication on where the problem is. If I pull and wiggle on the red cable, the horn goes on.

So now I need to dig deeper into the steering column.
Anyone here that have experience in this area. How to get into the steering column?
The obvious thing is the big nut in the picture above.
