I bought a new one and it does not have the wire. The original wire was placed under the large rivet built in.
What is this grounding and can I install without?
Thanks.
Mike

 

The horn button grounds through the steering shaft. Without the wire, the rag joint is an insulator and the horn may not work or may work poorly. I just made up a short length of wire with two ring terminals and put it under the bolt heads on either side.

 

Thanks Joe. Done. On to the vacuum mystery.