I have just put a new boss kit on my car and my horn doesnt work it has a wire that goes to the plate on the back of the bosskit, but it has no earth? the actuall horn button has to conectors on the back of it what would the other one be?
Quite often the button at the back has a metal loop coming out of it that touches the inside of the steering wheel to earth it. Sometimes that metal doesn't protrude enough to touch the wheel. Check that out!