Hi Jens,
I have a 4 spoke wheel as well. I don't think the diagram has the horn button in it. If you have the original wheel, remove the center area by twisting it counterclockwise( i think this is the right direction) and it should come off.
From there, you should see a button like piece sticking up out of the wheel assembly. It will usually have a black tip and bronze-like plunger (this is the horn switch). Pull this out and check that it is not cracked or grounding out against the metal. Mine had cracked and once replaced, it worked fine.
Hope this helps.
Marc
|