How Does the Horn Circuit Work?

If I remember correctly, a +12V (or +6V if you have the original system) wire, powered from a fuse that gets power when the ignition switch is on, goes to the + terminal of the horn. The other wire from the - terminal of the horn goes to the steering column tube (There is a spade connector for it at the end of the column tube under the gas tank). When the horn button is pressed, the column tube is grounded through a wire that goes through the column shaft, and is connected on a bolt on the steering coupler (a bolt of the steering box shaft). You have to check that the steering shaft doesn't rub on the tube when rotated and that the tube is insulated from the car chasis, otherwise the horn will honk by itself. If the shaft rubs on the tube, try to loosen the steering box clamp, and rotate it upwards / downwards to the appropriate angle so that the steering shaft is in the center of the tube.

Bill, '67 bug.

that agrees with the bently manual, so you do remember correctly. ;)

The wire that goes from the fusebox to the horn was originally a black wire with a yellow stripe. The wire that goes from the horn to the tube was brown.

The wire that goes to the steering box is also brown.