my 55 vicky 6 volt at times horn will blow other times not . it seems to be better with car revved up a bit.Could it bethe relay and is there a way to test?
Possibly a bad wire or lack of consistent contact in the steering column. Sometime dirt will get into the top of the column where the wire makes contact. Also check your connections at the relay and at the bottom of the steering column. Clean all connections.
Horns are a high current draw item so they need good wiring of proper gauge and a good clean ground pathway. They generally run with a ******** coil that has a set of breaker contacts to make it vibrate. The contacts have to be clean there as well as the relay and switch. Any extra resistance will rob necessary current for function.