Horn help!

[petrified_peach]

Hey folks, I’ve got a ‘73 C10 and the horn stays on. The black wire to the button is in good shape, I’ve taken the steering column apart to where the black wire ends and it still stays on. Tested resistance from relay end to the horn end of the black wire, relay end to first copper switch, and relay end to second switch, all test fine. I replaced the steering column last year and I remember the horn doing this with that one too. I’ve tried a new relay, I’ve tried a new horn and a new relay, and I believe something is just blowing up my relays. The last new one I tried now tests about 18ohms. With relay in and horn disconnected, the relay is really warm to the touch. Everything is wired according to schematics (no horn fuse), and I am STUCK. My next step was to try a 4 pin relay with a ground, anything else I should keep an eye out for? Or a different opinion on why it’s blowing relays?

Thanks

[bd]

Does the horn stop blowing with the relay unplugged?  Unplug the horn relay.  Use your ohmmeter to measure between the black horn button wire and ground.  Post the results.

[petrified_peach]

Does the horn stop blowing with the relay unplugged?  Unplug the horn relay.  Use your ohmmeter to measure between the black horn button wire and ground.  Post the results.

Do you mean the ground at the horn?

[Mr Diesel]

Sounds like you need to trace wires and connections. Something is probably shorting/grounding somewhere, like a wire pinched. Also check your horn button. These things are pretty old now and I've seen some disintegrate to the point they either don't work at all (bad connections) or "work too good" (connections touching when they shouldn't).

I once reassembled my master cylinder and brake booster on a car and had a constant "brake" light illuminated on the dash. Bled the crap out of the system over and over thinking it was warning light for pressure imbalance. Turns out I had accidentally pinched that sensor wire between assembled parts and it was constantly grounded out.

Edit:
Definitely follow BDs suggestion first. He is trying to help you troubleshoot the wire issue one step at a time.

[bd]

Does the horn stop blowing with the relay unplugged?  Unplug the horn relay.  Use your ohmmeter to measure between the black horn button wire and ground.  Post the results.

Do you mean the ground at the horn?

No.  The black wire that runs up the steering column to the horn button (i.e., the horn switch at the center of the steering wheel).  The symptoms imply that circuit is grounding.  FYI - the relay will become warm if the horn sounds constantly.  That in itself doesn't mean the relay is faulty.

[JohnnyPopper]

I've had to leave the center horn pad off due to it having a mind of its own.

If I push the left side of the metal pad receiver it stays on till I push the right side.

I think somewhere on this forum I saw a repair kit, just hasn't been a priority.

Although, thinking about it, the steering wheel does look kinda ghetto with out the pad. 

I think when I got this truck it had two horns, with different tones. I think I wore one out (a SoCal thing) because it doesn't seem as loud and seems to have a singular tone. Sound right?

[bd]

What ? ! ? ! ?

JP ! !     I can't hear you over the racket of your blasted horn ! !   




You really ought to get that fixed. 

[VileZambonie]

Hi and Low note horns on all of them. Add an air horn to the mix and you're winning.

[JohnnyPopper]

LOL 

Tempted to get a Train Horn...