Horn shorting out
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Joined: Apr 2000
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From: Central Pennsylvania
Horn shorting out
I have an intermittent problem with my '87 F350 horn wiring (or the horn) When I press on the button, most times the volt meter bottoms out. The other day I went in for inspection with the horn working and it worked fine till the next day when it started grounding out again. Should I start looking at the horns themselves? or somewhere near the fusebox or steering column. I read sparky's post about a 'rag' joint in the steering column. But this sounds like the power wire coming in contact with something. I've had the horn button apart and checked it out along with the wiring connections inside the steering wheel. There was some cross-contact between terminals and the steel support cone that I fixed. Maybe this melted a wire inside the column allowing it to ground out?
Any ideas?
Tony
Any ideas?
Tony
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Joined: Aug 1999
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From: Bel Air USA
Horn shorting out
If your horn wire in your steering column grounds out, your horn will blow continuously until you clear the ground. The horn wire in the column goes to ground through the horn button contact when you press the horn button. The horn button does not directly go to the horn. It goes to the horn relay coil. The other side of the coil is a hot wire. The horn button completes the ground side of the circuit which then energizes the horn relay. The contact on the horn relay then close thus putting 12V+ to the horn.
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From: Princeton, MN
Horn shorting out
So by his explanation, the horn relay would be on the "down current" side of the circuit, after the horn switch, so that could be a potential source of the problem. With the problem only happening when you hit the switch, it is going to be the switch or after it, not before. Te horn itself should be fairly easy to test, no? You could just energize it and see if it sounds. Don't knock your head on the hood if it does!
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From: Central Pennsylvania
Horn shorting out
So in your opinion, kioolt, I should either look at the horn relay or the horns themselves. (or maybe the fusepanel) I could easily direct wire to the horns to see if they work. (reading buckarcher's post as I type, will be sure to wear hardhat when checking horns).... but one other thought. What if the ground side of the horn button was "shorted ...... to ground'..... would that or could that be a problem, by 'not completing the circuit to the horn relay?.... What am I smokin'?
Thanks
Tony
Thanks
Tony
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From: Princeton, MN
Horn shorting out
Originally posted by Tony G
but one other thought. What if the ground side of the horn button was "shorted ...... to ground'..... would that or could that be a problem, by 'not completing the circuit to the horn relay?.... What am I smokin'?
Tony
but one other thought. What if the ground side of the horn button was "shorted ...... to ground'..... would that or could that be a problem, by 'not completing the circuit to the horn relay?.... What am I smokin'?
Tony
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From: Central Pennsylvania
Horn shorting out
Well, according to the wiring diagrams for both '86 and '87 schematics, I only have a horn relay *IF* I have cruise control. 
I don't have cruise control, So I think I'm back to horns or shorted wires or fuse panel??
Tony
I don't have cruise control, So I think I'm back to horns or shorted wires or fuse panel?? Tony
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From: Bel Air USA
Horn shorting out
After reading Tong G's last reply I went and got a wiring diagram for an older Ford. It's for a 78 Cougar and yes it does not have a relay if the vehicle doesn't have cruise control. Also my description of the horn button switching the ground side is not correct for that year vehicle regardless of the cruise control. Both with and without cruise switch the hot side. It seems that on older Fords they did switch the hot side. That being said you could have an intermittent short in the steering column on the switched horn button wire. You could troubleshoot this by pulling the wire off of the horn. Put one lead of the ohmmeter on the wire and the other lead to ground. Do NOT push the horn button. The meter should read open or infinity. Have someone turn the steering wheel. There should be no change. If you read anything to ground you do have a short on this wire. Good luck.
Last edited by kioolt; Feb 10, 2003 at 08:12 AM.
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Joined: Jan 2003
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Horn shorting out
Well I have had a problem such as this and after checking the wiring for the correct 12v current it turned out to be the horn
I replaced the horn and it works perfectly
I replaced the horn and it works perfectly
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From: Central Pennsylvania
Horn shorting out
Well, here's the latest update: I happened to lose a headlight lens over some bumpy Pa backroads. $100 for that part alone. It was the left side headlight and while I had the headlight off, I checked over the horns. I bought some new ones at Napa earlier in the week as a forethought.
Sure enough, whoever had replaced or moved the horns before me ( I hope it wasn't from the factory) had managed to put the wire to one of the horns behind the mounting bracket and time and friction had rubbed the insulation off the wire. In addition, the other horn had filled up with dirt and water=mud. So, without taking the steering column apart, I did have an easy fix and now have nice loud horns.
Tony
Sure enough, whoever had replaced or moved the horns before me ( I hope it wasn't from the factory) had managed to put the wire to one of the horns behind the mounting bracket and time and friction had rubbed the insulation off the wire. In addition, the other horn had filled up with dirt and water=mud. So, without taking the steering column apart, I did have an easy fix and now have nice loud horns.
Tony
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