1987 Ford F150, 302 5.0L automatic.
The horn of my truck has been removed, but when I push the steering wheel to activate the horn, I do hear a click. I replaced the horn and still no sound, just a click (I returned that horn). Having never done anything involving grounds/ wires/ electrical with a vehicle, what are some possible problems and solutions? I’d love to have a horn because there are so many people driving while texting
Vehicle horns sit up front where they’re exposed to rain and road chemicals. Once that spray gets into the horn’s innards, it can short out the coil and kill the horn (and blow the fuse in the process). But an inoperative horn can also be caused by a bad horn switch in your steering wheel, a broken “clock spring” under the steering wheel, a bum horn relay, a broken wire or a corroded ground. Here’s how to check the most likely suspects.
Start with the fuse. Refer to the owner’s manual for its location. If the fuse is good, jump power directly to the horn with a homemade fused jumper. If the fuse blows, you’ve got a bum horn. If the horn makes a clicking sound, the problem could be a poor ground connection. Clean the horn’s ground connection and try powering the horn again. If the horn still clicks, you’ll have to replace it.
From what you say and the problem it appears that the relay is working but there may be a problem with the relay contacts, the wiring after the relay to the horn, or the fused power to the horn. Start with the fuse and if that is okay try swapping the horn relay with another similar relay to see if that helps. If not then check the continuity of the power wire between the relay output and to the horn.
It works slightly differently depending on whether you have speed control or not. I presume you do, b/c that’s the only configuration that uses a horn relay. First check fuse 16. The horn switch is part of the speed control switch ass’y, and grounds the horn relay coil (DB wire) when the horn switch is depressed. If your speed control functions normally, the ground connection is probably ok, but the switch could still be faulty. the horn relay should have a Y/LG wire attached. It should measure battery voltage when the horn switch is depressed, and that connects to a DB wires which go to the two horns, one on the left for the low pitch, one on the right for the high pitch.
So check that the horn relay is powering up the horns. If you got battery voltage to the horns and they don’t honk, either both horns are faulty, or their grounds are making a good contact.
The horn relay appears to be located inside the passenger compartment, under the left side of the dash, near the speed control gadget.
Okay, thank you for the tips and advice. I will look into all of those possibilities. Electrical stuff is all new to me, so I appreciate the help
One thing you can try is substituting the load. Unplug the horn and patch in a headlight bulb. If, when you press the horn buttpn, the bulb illuminates you know the circuit is good. If it doesn’t illuminate, you can guess the horn is good and know something in the circuit has failed.
Where can I find the grounding for the front horn ?
If there is only one wire on the horn it grounds through the mounting plate into the chassis.