I have same problem it is not horn switch any ideas.

And the belly button switch goes through grab handle horn switch. If you have no emergency reverse on a 112, the horn switch is bad. They do this for freezers, where there is a plastic curtain you have to drive through. you hold horn to to go into plastic curtain. If the curtain hits the belly button switch, you dont stop and go into reverse, because the horn switch opens the circuit of the belly button or emergency reverse

Yep, Raymond thinks that if you can't beep your horn then you shouldn't be driving fast.