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I have the column out on my 38 1/2 ton truck and don't really know how the horn button is supposed to work. Inside the column is some kind of plastic bushing with a brass ring on top, from the ring is a single wire that exits the bottom of the column. How is this single wire suppose to activate the horn? Should there be another wire or should this brass ring be grounded or does the horn button itself somehow ground the wire? any help on how the horn button works or what a good test to see if it will work would be greatly appreciated.
Thanks,

pushing the horn button puts a ground on that wire to complete the circuit to the horn, use an ohmeter to check, from the wire end to the column tube, you should get continuity when the button is depressed

Bill

Should there be a spring under the horn button or just the rubber and the two prong fork thing that goes through the steering wheel?

Bill is right, the wire only caries the ground to the horn relay. The horn relay has power coming in and a wire going out to the horns. To activate the relay, you supply a ground to complete the circuit. The actual push button has two wire prongs that rub on the steering wheel hub which is connected to the gear box through the steering shaft. The shaft gets it ground through the bearings and steering box housing, which as you know is connected to the frame. Thats a lot of connections that need to be clean and tight. The top bushing which you see in the column is a wood/rubber/man made type of material which insulates the brass ring from the steel tube. GM designed the horn to work off ground for a safety reason. If you was to run a hot wire up the steering column tube, you risk the chance of a direct short from chaffing. By using a ground, the most that can happen is the wire shorts to ground and the horns blow, annoying yes, but still better then sparks and possible fire you could get with a positive wire.

I believe new bushings can be had if yours is worn in the center. I made one using a piece of teflon drilled and fitted with the original brass ring and new wire. Mine was well worn letting the shaft flop around. You will also find the push button has very little down ward travel so the wire prongs set pretty close to the brass contact. its possible to honk the horns when turning hard or really working the steering wheel. If the bushing is really worn, the brass contact can hit the shaft causing unwanted honking.

The wire exits the column at the bottom through a rubber grommet, be sure the rubber is in place.

To test the horns, apply direct positive voltage to the wire contacts at each horn.

If the horns work, follow the wire going to the horn relay. This should be mounted somewhere on the firewall, http://www.chevsofthe40s.com/images_product/large/1116775A.jpg. One wire will be hot, one ground, and one to the horns. The ground will only be active when the horn button is pushed. Hot wire will be direct battery voltage, 1937 has a circuit breaker feeding the amp gauge and horns. A quick ground to the relay will let you know if its working, and volt meter or test light will tell you if it has power. If everything so far works, you are down to the horn button and wire.

Joe

http://chevy.oldcarmanualproject.com/parts/1929_54/396.htm

No spring, the rubber push button is the spring.

Thanks that helps alot

To answer your question about a spring. They didn't come from the factory with a spring under the button. There was an aftermarket spring that you could purchase that helped make a more consistent ground. The issue that sometimes arises is to complete the circuit and honk the horn the S wire must contact the sides of the holes AND the brass ring on the mast jacket bushing at the same time to complete the circuit. Sometimes that doesn't happen. With the spring that connects to the S wire and rests on top of the steering shaft, it makes contact every time. I found some of the springs on ebay a couple of years ago and bought them all. I have one in my car and one left as a spare. With a bit of time you can make one if you find it necessary. If you need to do that drop me a PM and I'll send you a pic of the one I made & used before finding those on ebay.