49 Chev 3100 Horn issues
 

Hope someone can help me here. Installing a new wiring harness on my 49 Chev truck. When I hook the wires up to the horn it blows constantly. Was told to disconnect the ground on the horn button but when I plug in the horn relay the horn still blows. I have RED,Green & black wires going into the horn relay switch. Following the black to the ignition switch as it is a horn relay ground, the green wire goes to the horn. Any suggestions?

Re: 49 Chev 3100 Horn issues
 

welcome...sounds like its grounded somewhere..i think the green wire going to the horn button is the ground

Re: 49 Chev 3100 Horn issues
 

in order to make things easier to work on, try using a light instead of the horn. watch for the light to turn on instead of the horn blowing your ears out and annoying the neighbours.
disconnect the wire to the steering column, then power up the horn relay. common to have a problem with the steering column grounding the wire or a problem with the horn ring grounding.
check the relay for welded contacts
check the relay for power where it should be and grounds where they should be
it's just a horn, don't think too much into it. look at a wiring diagram if you are a bit lost on how it works, then probe each contact on the realy to figure out where the problem is

Re: 49 Chev 3100 Horn issues
 

I was just thinking back to one of these old trucks I helped out on. no horn relay till 50 something. they used to be just a hot wire to the horn and the ground was in the column. I did a quick check online and came up with this. maybe helpful.
end of the day,I havefound most "always blows" problems are in the steering column. there should be no ground there until you touch the horn contact

https://www.stovebolt.com/ubbthreads...&Number=618509

Re: 49 Chev 3100 Horn issues
 

Re: 49 Chev 3100 Horn issues
 

I haven't seen anyone reply that it could simply be the horn?? did you try another horn, or as said, try the light, did it come on constantly? Do you have 2 horns and do they both come on as you're stating? I've had a horn come on constantly and it turned out to be the damned horn. That of course was another problem.

Re: 49 Chev 3100 Horn issues
 

The majority of the time it is going to be somewhere between the horn button and the horn relay. Usually because the insulation deteriorates on the wire and it shorts out.

That is the majority though as I have had stuck relays and horns that were stuck on. If I am not mistaken the horn in my 71 GMC is still disconnected after it did the wants to honk all the time thing and I disconnected it at the horn.

I'd disconnect the wire to the horn button at the relay and see what happens as that eliminates that. Then you go from there in your trouble shooting.