Horn grounding issue on +2...

[mibux]

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!

[RobertMaulden]

Is the earth wire from the horn slip ring broken?
Is the horn "pencil" actually making contact with the slip ring?

[Craven]

May help
https://rimmerbros.com/Item--i-GRID005783

[pharriso]

May help
https://rimmerbros.com/Item--i-GRID005783

You need part # 130581 in the parts diagram.

[bast0n]

Phil is correct. D

[Steve Brooks]

Hello chaps, I had the same problem a while ago and bridged the gap on the steering joint with copper wire as all the earth straps seemed to be to long.Regards Steve

[Hawksfield]

Hi
I recently had a lazy horn not operating every time found it was a high resistance on the splines of the steering column upper, had to slacken of and pull steering wheel in and out to clear corrosion and re tighten. now ok.

I could not believe that a tight coupling clamp could go high resistance.!

[nmauduit]

Hello chaps, I had the same problem a while ago and bridged the gap on the steering joint with copper wire as all the earth straps seemed to be to long.Regards Steve

Fwiw on my Federal S4se there is a short wire across the steering joint to maintain continuity so that grounding of the horn wire can be controlled by the horn button...

[RichardHawkins]

My 1968 S4 also has a short earth braid across the coupling on the steering column.

Richard Hawkins

[mwhitaker]

My Federal 69 S4 also has the ground strap across the steering coupling. My horn issue turned out to be due to a fractured horn pencil-replaced it with one from a TR6/MGB-slightly longer and a slightly tighter fit than before but works very nicely with mild pressure required and no sounding off when turning the wheel!

Mark
69 Elan S4 DHC
45/8396