Haha, what a simple question!! But where is the horn mounted for a Kombi 1975 model?????
I'm having some problems, as it isn't working, and my wiring system seems to be the issue, but i'm stuffed if I can find the horn itself.....

Underneath the "chassis" on the passenger side.
hth
Brilliant!!
Problem solved... was able to trace the wires and find the fault.
Many thanks Modulus.