Baffled by this one. Everything about the horn circuit checks and test functions up to the horn button itself.
Horn button and associated plunger all pass bench tests. However a ground from the steering column or steering shaft is missing.
If I attach a ground cable to the steering shaft above the universal, everything works fine. The steering rack itself has a working ground. But, the rubber bushings in the universal joint appear to electrically isolate the shaft.
It does not appear in the manual that any kind of jumper was intended to bridge this. Yet the horn did work in the past. Have no idea what has changed.
Any suggestions? Thanks!