This one's bound to run as long as the dipdtick thread
When I got my car first the horn didn't work, turned out to be the spring loaded contact between the steering wheel itself and the whatchmacallit behind. It did require removal of the steering wheel, a bit of re-engineering with araldite and it's working fine since. Just do an electrical trace from the horn button through to the horn itself, not forgetting the fuse
John