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1947 - 3100 with stock 6 volt system. When I depress the horn button on the steering wheel the horn makes a very faint sound which makes me think it is getting power. You can hear it with engine off but not if it is running. Anyone have any suggestions regarding this issue?
Thanks, ray durham

Do you have a good ground on the horn? If using a multimeter, can you get a 6v reading when pressing the button?

Will check that out when I have help.

There is no ground on a stock horn which has 2 wires.
Ground is supplied by the horn button.

I have the stock horn mounted on the manifold in front of the carburetor with 2 wires going to it. One is red and the other is black. I wonder if my issue might be at the steering wheel where the horn button is located.

It's possible. First, check to see if your horn actually works by using a couple jumper wires directly from the battery

After you jump the horn and confirm that it functions, look at the wire inside the steering column.

About 2/3 the way up, the wire enters the column and is connected with a bullet connector or spade connector.

Hot wire it from that point. If it works, the problem is with your horn button and associated components on the steering wheel.

I ran power direct from the battery to the horn and it blows loud and clear. Ready to check at the steering wheel. How do you get the horn pad off to get to the horn parts at that location? I'm thinking when I press the horn pad it is not grounding like it should.

It just pries off with a small flat screwdriver.

Jumping on this recent thread as working on my horn. I have a 6 volt positive ground ‘51 GMC.

I just tested the relay and the horn and got the horn to honk by touching a wire from the “S” of my relay to ground.

Once upon a time my horn button worked so I think my issue is the wire going down the steering column. (it’s the last piece of cloth wire on my truck…everything else is replaced with plastic insulated wire).

Any tips on running a replacement? Should I use #10 AWG so the ground is good? I’m worried my old wire will break as I pull the new wire through.

Also, I’m not sure I’m Hooked up correctly. Here are some tests I’ve done:
- I tested my relay as per this site ( https://devestechnet.com/Home/ADWiringSystem ) and also bypassed my horn button to get the honking
- There are 2 wires on the horn, one is connected to the hot wire of the voltage regulator and the other is grounded.
- I disconnected both wires and tested ground from the horn body (none) and from each of the terminals on the horn (none)
- I found continuity across the 2 terminals of the horn
- wiring diagram shows that I should be getting hot from the Ammeter but I’m getting it off the voltage regulator. Should I change this?

Use the same size wire up thru the steering column. The only load on the ground wire to the button is the relay coil, which is minimal, and definitely doesn't need #10. You'll need to remove the steering shaft bushing from the column to make the connection to it.
This means your relay is set up correctly.
If it's connected to hot and ground, it should be blowing constantly. The relay must be between the regulator and the horn.
That means the terminals on the horn are isolated from ground, which should be correct.
Means that the windings in the horn motor are OK.
Doesn't really matter where the power is coming from, but as in above, it needs to go thru the relay.

Otto,
What size is the nut that holds the steering wheel on and is it SAE or Metric? I have a new top plate and contact spring I want to install. ray durham

I'm not Otto, but the steering wheel nut is definitely SAE. But I don't have the size handy. I'm going to guess 3/4" or so.

And he thanks the Lord every day for that.

AMEN!

Today I decided to try adjusting my horn points because it barely makes a sound. More like the bleating of a lamb!

I took the horn out and took the horn apart and found the points touching so I checked the air gap, sanded the points contacts and adjusted them to spec (0.027”). Then I tried a direct contact to the battery and nothing. Then I hooked it up in my truck as before going through the relay and still nothing. Not even the bleating

I guess I need to go back to square one and test for continuity and/or resistance across the terminals? Maybe my previous test was faulty because the points were touching and I never actually tested the horn’s coil….

Suggestions appreciated

Tested voltage as I press horn button and getting 6 volts. Testing for continuity across terminals on horn and getting nothing now that I adjusted my points gap so I’m assuming the horn is shot.

If it won't honk when fed 6V directly from the battery, then the problem is at the horn itself. I could double check the points, maybe hit them with some spray contact cleaner. With the points closed you could measure across the terminals with an ohmmeter. If you get an open circuit (infinite resistance, the coil in the horn is shot. But if it was bleating previously, that means the coil is OK.