NO HEADLIGHTS 1994 FORD EXPLORER - HELP PLEASE

[davisp]

Hello all. I find this forum most helpful but I cant find this problem.

1994 ford explorer. leaving for work this morning and I turn on the headlights and all I have are the park lamps, tail lamps, and brake lights all work. No headlights. I try the high beams, they dont work, but the high beam flasher does work. Check all the fuses cant find anything. I was in a hurry so I was going to run a jumper wire from the park lamps to the headlights as a temp fix.

Well as I unplugged the bulb assembly all the parking lamps went out, but the headlights turned on at that very instant. I checked and the fuse was blown for the parking lamps. So I put a new fuse in and now im back to the original problem. Parking lamps with no headlights. This really baffled me.

Anybody have any suggestions?

Thank you

 

[Rhett]

The headlight switch can go bad on our trucks, which is fairly common since all that power has been frying it for 20-25 years. I'm not saying that is definitely the problem, but it's a possibility if your wiring is otherwise intact. You can bypass the power running thru the switch with your own harness, or buy the one I'm running.

I am running the harness from LMCTruck at this link:
Truck Parts and Truck Accessories

 

[Roadrunner777]

The part you start with unplugging the lamp assembly has me a little baffled, so I'm ignoring it for the moment. I agree with Rhett on both counts.

The way the headlight system is designed and wired is not ideal. Power to the headlights has to go from the battery to the switch and out to the headlights through the smallest wire they could get away with. And, the switch is the lightest duty they could get away with as well. Result: Burned out headlight switches, and reduced voltage to the headlights because of the wire size and length. I measured voltage at the bulb compared to battery voltage and there was a 1.5 volt drop because of the wiring. This is significant, given it's a 12V bulb.

This is such a problem that companies have been making aftermarket wiring harness such as the one Rhett talks about. It has heavy wiring and relays so the path from the battery to the headlights is shorter with heavier wire. And, with the harness, the headlight switch only switches the relays, so the switch won't burn out.

Advice... first, replace the headlight switch. I think it failed in such a way that maybe it caused the weirdness of unplugging the lamp assembly. It's not an expensive part, but I think you have to remove the dashboard bezel, which is always a chore. The harness may or may not be worth it depending on how and where you drive. I drove a lot at night in the country with deer, so it was an easy decision for me, and worth every penny. Your mileage may vary.

If the headlight switch doesn't do it, post back, I'll get out the wiring book and help you track the problem down, but I'm about 90% on the switch. Good Luck!

 

[Dragon90815]

Some times the filament can be broken and by moving it cause it to come back on but will go off when bumped. you should be able to see if filaments are good on both high and low beams. bulb number 9004