The Stovebolt Site Forums The Shop Area The Electrical Bay Horn wiring 1939 Chevy (early 40's too?)

How doe sthe horn wiring work for the 39 Chevy truck? There is a wire that exits the lower sterring column, whats it connected to in the column? How does the horn button work, should there be wiring to that. How about the horn relay switch. where do those wires come from? I have alot of blanks in this particular wiring situation on this 39.
Does someone have a wring schematic or a picture that could help me.
Thanks
"1fine3"
David

1Fine39,

Welcome to the Stovebolt. I have enclosed a link to a '39 truck wiring diagram. It shows the horn as wired in the conventional manner which is 'hot' all the time.

The button in the steering wheel supplies a ground for the horn which completes the circuit and makes it toot!

This early system had no horn relay.

http://chevy.tocmp.com/chevywiring/pdf/39truck.pdf

Stuart

Stuart,
Thanks for the diagram. When I disassembled the steering column, the only wire hooked to anything was a bare wire protruding from the bottom of the steering column. There was no wire that was connected to the horn buttom itself.
Are you saying that the wire should go directly to the horn buttom, then when you push the buttom, one of the tines touches the steering column (grounding it), causing the horn to tute.
The diagram shows the button wired directly to power.
Thanks
David

David,

If you look at the diagram again, you will see the horn has two wires attached to it. One wire comes from power and enters the horn. Another wire is shown going to a horn button.

The power wire enters the horn and terminates on a vibrator that is insulated from ground. The second wire that goes up your column to the horn button completes that circuit and supplies ground when you depress the horn.

Does this make sense? That wire sticking out of the bottom of the column travels up to the steering wheel, and through combination of insulated little discs, springs and what-not, allow you to turn the wheel, yet be able to ground that circuit when you mash the button...toot toot!

I sure hope this is how it works!

Stuart

The horn button has an "S" wire that completes the ground when the button is pushed. Your mast jacket bushing (may be a bearing in '39) has a copper ring around it that the "S" wire contacts when the button is depressed. In theary the "S" wire will also contact the side of the steering shaft at the same time to complete the circuit. In practice the set up is pretty mickey mouse (at least on my 38) and is kind of hit or miss. The "S" wire is held in place by the same rubber that holds the button. You can get the whole thing at any of the vendors. If by chance you have the accessory "Town & Country" horns you'll need a relay for those. The stock horn that mounts to the manifold is as Stuart advised, not requiring a relay. A lot of folks put an accessory horn button on the side of the steering column and run a wire through the dash to bypass the stock set up. That's how my 38 was. I'm still in the process of getting the stock set up to work "right".

To add to what Tiny said, the top mast bushing is insulated so the steering shaft (3/4" solid steel) does not touch the outer mast tube. The steering wheel is connected to the steering shaft with a key way and nut. This makes a solid connection to ground by way of the steering shaft, steering box, frame, and finally back to the battery. The "S" wire he talks about is shaped like a "S" and is under the horn button. It has two long 3" legs that go through the steering wheel and down towards the mast bushing. The two legs drag along the steering wheel holes making contact as they go. This is how the circuit is completed. On top of the insulated bushing is a brass ring. The wire you see at the bottom of the mast is hooked to the brass ring. As the "S" wire drags along the wheel, it completes the ground circuit by contacting the brass ring which sends the ground down the wire out to the horn. No relay is needed. If you add late model horns, just add a horn relay and use the horn button just as it is. Add again quoting Tiny, they are not the best set up. It will work, you just have to really push and sometimes wiggle it a bit. Joe

What is the correct process for removing the horn button on the 39 light delivery truck?

In the 46 you unscrew the center button. One other thing I learned on my 46 is the outer sleeve of the steering column can be adjusted in and out of the steering box which affects how the horn button functions.

Just pry it up. The rubber fits in a groove in the steering wheel hub.

Thanks