My horn did not work when I got the car. Sometime after changing to the Momo steering wheel and its horn button with the Porsche crest, I pushed the button, probably by accident and was very surprised to hear a sound kind of like what might happen if you stepped on a cat's tail.

So I've thought about buying a set of Hella horns and a new relay. The electrical circuit is probably fine, it's just that I have an old cat.

In looking at the wiring diagram the hot side of the horns are black and yellow wires which go separately to the horn relay. A red wire goes to the number 4 fuse. The horn button is across ground to a white and brown wired to the horn relay. The relay is normally open. Pushing the horn button grounds the coil in the relay, closing the switch which puts 12 volts on the horns. You should see +12 volts on the wire to the horn button.

A note from Bob Wonsetler ('66 912) points out that the brown ground wire from the cigarette lighter to the firewall is a necessary part of the horn circuit.
121501-515 If you have a standard steering wheel, there is a little compressible gizmo that fits in the steering wheel and is part of the circuit.

You can see the hole in the steering wheel where this connector fits.
121501-517 The horn button works against a rubber cone which acts like a spring holding the botton way from the closing the circuit. This rubber cone gets old and bad as in this picture, but can be purchased as can the the gizmo. I've seen them advertised in Tweaks or Automotion catalogs. Be sure you can measure +12 V on the horn wire in the center of the steering wheel with the ignition on. The horn should bleat if this wire is shorted to the steering column.
Last modified: Sat, 15 Dec 2001


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