While im waiting for the rain to stop I'm doing a little research to make my tinkering go smoother. I used the search button a bunch but didnt find any info solid enough to go on.

1) No horn

2) No hazards, but my blinkers work.

and last but not least 3) The headlights work but after a bit they start to go on and off. The rest of the lights stay on so its probably just a lose wire or ground somewhere.

Im more worried about 1 and 2 because im not sure where to begin with them (besides fuses of course)
Any input would be greatly appreciated

 

Scratch that, have hazards now.

 

what was the problem with your hazards?

Mine don't work either, PO swapped in a later model steering column. everything else works but those.

 

Not too sure, took dash apart shook a few wires an on they go haha.

 

yeah... I "fixed" my tail light that way too

 

Works for me haha. Now onto the horn...

 

The on/off pattern you're seeing with the headlights is from the internal circuit breaker cycling. This is because you have a short somewhere downstream of the headlight switch. Check the wiring between the switch and the headlights for pinching or frayed insulation.

The horn could be a number of things. As a sanity check, disconnect the wire going to the horn itself and make sure it has power with the horn pad pressed. What year truck is this? Does it have cruise? These determine whether or not you have a horn relay.

 

74 f250 no cruise

 

Did you try this yet?

You have a horn relay. Do you hear it click when you press the horn pad?

 

I haven't been able to get out and check it out yet bc of the rain an classes. Where is the relay located?

 

This can be and usually is just an old worn out headlight switch, the contacts get worn and don't make good contact and generate heat, of course the heat causes the THERMAL breaker to cycle...

 

Okay.. finally got outside for a bit. I have no power going to the actual horn itself when the button is pressed, I also tested the button to be safe and it works. What would be you guys' next step?

And for the headlight thing.. is there anyway of testing the switch for that without buying a new switch?

 

1) Do you hear the relay click? If not, check for power at the relay. If the relay has power, but doesn't click, replace the relay. This would be consistent with you not getting power at the horn in the first place.

2) Disconnect the headlights, then disconnect the connector to the headlight switch, opening the circuit on both ends. Check for continuity between the power to the headlights from the switch at the connector, and ground. If there is some finite resistance, then you have a short in the wiring which would explain the cycling breaker. However you do it, you need to eliminate the possibility of a short before replacing the headlight switch, because as far as we can tell at this point, the headlight switch is just doing its job.

 

This is how I nailed down my blinking headlights. There is a square four pin connector not too far forward on the inner fender of where the windshield washer connector is, there is also one over on the other side right below the battery on the inner fender. Run your lights and when they start blinking go and disconnect one of these four pin connectors, this will shut down that whole corner of the truck, so if the headlight on the other side stops blinking you just found where your short is at. If the headlight on the opposite side is still blinking reconnect the connector and pull the other side apart and repeat. If they still blink after checking each side pull the connector under the rear of the truck (same four wire looking). Mine was a short in the front pass side parking light wire chaffing on the rad support. It would blink everything from this even my dash lights. If disconnecting all three of these spots doesn't work your problem is between the switch and your connectors. check your dimmer switch, had one of these corrode so badly it was shorting the system out.

 

Fmc400 where is the relay located? I'm working off my phone or else I'd use the search.

And wish me luck kingford, I'm going to try your way real quick an ho