Headlight Help
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New User
Joined: Feb 2013
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From: McKinney, Kentucky
Headlight Help
Hello everyone, have a 86 6.9 reg cab 4x4. I have tail lights front and back turn signals and all parking lights but no headlights. I cant see the actual bulb good enuff to tell if its shot, how would I go about testing the head light, and which fuse under the dash woud I be looking at if it were to be a blown fuse. Thanks in advance.
Posting Guru
Joined: Jan 2013
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From: VA
If both of the headlights went out at the same time, then it's probably not the lights themselves. The cover of your fuse panel should have a layout of what fuses go to. If not, there aren't that many fuses, so just pull them one at a time to see if one's burnt.
Postmaster
Joined: Feb 2011
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your headlights don't have a fuse over them, just the fusible link up by the battery.
have you done any recent electrical work on the truck that might have something to do with it? when i removed the stock alternator wiring in favor of a higher output setup, i lost headlights until i put a jumper wire across one of the plugs i disconnected.
to test the headlights themselves, you'll want two test wires, preferably with alligator clips. with the headlight removed and laying on the front of the truck, connect your wires to the truck battery and the bulb, and see what happens. try your wires in a few different orders, one pin is ground, the other 2 are hot for high or low. doesn't matter what order you're in, just expect to get a high and a low setting.
or if you're afraid of wires, put your headlight bulbs in a truck where things work, and use it for a tester
have you done any recent electrical work on the truck that might have something to do with it? when i removed the stock alternator wiring in favor of a higher output setup, i lost headlights until i put a jumper wire across one of the plugs i disconnected.
to test the headlights themselves, you'll want two test wires, preferably with alligator clips. with the headlight removed and laying on the front of the truck, connect your wires to the truck battery and the bulb, and see what happens. try your wires in a few different orders, one pin is ground, the other 2 are hot for high or low. doesn't matter what order you're in, just expect to get a high and a low setting.
or if you're afraid of wires, put your headlight bulbs in a truck where things work, and use it for a tester
Postmaster
Joined: Feb 2011
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it would be near the right battery i believe - but i'm in a van body so my layout is a little different. they usually won't blow unless you really short something out, and you usually have more to com,plain about than headlights if thats your case.
that said, also check your headlight switch on the dash, and the high beam switch on the floor.
that said, also check your headlight switch on the dash, and the high beam switch on the floor.
Senior User
Joined: Oct 2012
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From: Co
Am I the only one that would just install a new bulb and see what happens first? IMHO bulbs are cheap and quick and it never hurts to change them anyways. If that doesnt work its time to get out the test light and start checking for power from headlight connectors back (headlight->switch(s)->battery)
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Posting Guru
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From: VA
Am I the only one that would just install a new bulb and see what happens first? IMHO bulbs are cheap and quick and it never hurts to change them anyways. If that doesnt work its time to get out the test light and start checking for power from headlight connectors back (headlight->switch(s)->battery)
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Senior User
Joined: Oct 2012
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From: Co
Yep you do but its still just as easy if not easier then just replacing the bulb behind the lens and is typically cheaper (plus you never have to clean a lens)
i ain't rite
Joined: Mar 2005
Posts: 65,565
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From: Marlboro Mental Hospital.
get a test light. ground one side, and remove the plug from the dimmer switch. with the headlight switch on, test for power. if i remember correctly, the center contact is power input. if you have power going into the switch, use a small jumper wire and jump power wire to one of the others. if lights come on the dimmer is bad.
if no lights, bulbs or wiring is bad. my bet is bad dimmer/ wire pigtail. i have replaced many of them due to corroded contacts in the wire and contacts rotted off the switch.
if no lights, bulbs or wiring is bad. my bet is bad dimmer/ wire pigtail. i have replaced many of them due to corroded contacts in the wire and contacts rotted off the switch.
Fleet Owner
Joined: Jul 2006
Posts: 20,381
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From: Mi'kma'ki
yeah,im betting the issue is what Tom speaks of.don't be surprised to figure it out instantly without requiring the meter.you might pull the headlight switch out to see it brownish in spots along with the pigtail and obviously in need of replacing.
ford thought it wise to skimp (due to price no doubt) and run full power up to the switch and let it handle the full load rather than letting some relays handle the job.
replacing the switch,pigtail and installing a couple relays for low/high is a good idea if you find this to be the issue.you'll have brighter headlights too.
Whiter Whites, Brighter Brights .: Articles
ford thought it wise to skimp (due to price no doubt) and run full power up to the switch and let it handle the full load rather than letting some relays handle the job.
replacing the switch,pigtail and installing a couple relays for low/high is a good idea if you find this to be the issue.you'll have brighter headlights too.
Whiter Whites, Brighter Brights .: Articles
Post Fiend
Joined: Nov 2005
Posts: 7,437
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From: Charles Town, W bygod Va
I did the relay upgrade on both of my trucks. I made my own harness because I have plow lights also, but for a normal setup, you can buy a kit that is plug and play for about the same $ as making your own. (From LMC?)
