85 F150 Electrical Issues with exterior lights
10-30-2018, 07:22 PM
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85 F150 Electrical Issues with exterior lights
I have been working on this truck for a while now and finally have it almost to the point where I can use it regularly. However, the headlights only work when set to the High Beams. I took out the old headlight and replaced it. No luck. Then cleaned and tested the female connectors that power the headlights and the High Beam post was receiving roughly 12v but the low beam slot on the connector was only being sent 0.6v when the switch in the cab was set to low beams.
Would my best bet be to replace the female connectors or try and get to the dimmer switch in the cab and change it out?
On top of all that, I discovered that none of the turn signals work on the truck all of a sudden. I pulled the flasher unit out from the fuse box and tested it with the multimeter and it showed 0.5ohm resistance. I'm not really sure if that is the best way to test them to see if it's bad, or if it'd be best to just buy a new one for the money and pray it works. Flasher is a Wagner 552 12v.
Would my best bet be to replace the female connectors or try and get to the dimmer switch in the cab and change it out?
On top of all that, I discovered that none of the turn signals work on the truck all of a sudden. I pulled the flasher unit out from the fuse box and tested it with the multimeter and it showed 0.5ohm resistance. I'm not really sure if that is the best way to test them to see if it's bad, or if it'd be best to just buy a new one for the money and pray it works. Flasher is a Wagner 552 12v.
10-30-2018, 08:46 PM
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We haven't, so for us to help, you need to put ALL its details & history into your signature as this caption explains:
(phone app link)What about the parking lights?Are you saying the truck only had 1 headlight? Or did you mean the headlight SWITCH? Or the hi-low switch? What exactly did you replace it with (brand, PN, source)? Did the replacement pass the same test that the original failed?Don't rely on luck. And we can't help you without details. What exactly happened, or didn't happen?Where exactly was each probe, and what was each switch (ignition, headlight, hi-lo) set to?No, you should never replace a part until you KNOW which one has a problem, and what that problem is.Then why did you test it that way? Do you have a Haynes manual? Have you read it?
(phone app link)Do you really expect that to work? If that's your method, you should buy a new TRUCK - not a PART.
(phone app link)What about the parking lights?Are you saying the truck only had 1 headlight? Or did you mean the headlight SWITCH? Or the hi-low switch? What exactly did you replace it with (brand, PN, source)? Did the replacement pass the same test that the original failed?Don't rely on luck. And we can't help you without details. What exactly happened, or didn't happen?Where exactly was each probe, and what was each switch (ignition, headlight, hi-lo) set to?No, you should never replace a part until you KNOW which one has a problem, and what that problem is.Then why did you test it that way? Do you have a Haynes manual? Have you read it?
(phone app link)Do you really expect that to work? If that's your method, you should buy a new TRUCK - not a PART.
10-30-2018, 10:52 PM
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I've updated my vehicle information.
To answer your questions in order, the parking lights are also out, I have not got around to testing them yet.
The truck has both headlights, however, after replacing the first one with a new unit I stopped to check that it was operational before moving on to the second headlight. The new unit is a Sylvania H6054 Sealed Unit. That is when I discovered the issue. So I began searching for the issue. At first I thought maybe the female connectors were just clogged up with stuff so I used compressed air and contact cleaner to get any gunk out of them, then retested. Still had no low beam. So I unhooked the female connector, with the truck running and the headlight switch turned to the High Beam setting, placed the negative into the right post slot (Black Wire) and the positive into one of the other slots (I honestly can't remember if the top or the left was high beam). I was able to get a reading of 12v out of the high beam slot and then I switched the selector switch back to Low Beam in the cab and moved the positive lead from the multimeter to the last unchecked slot on the connector and only showed 0.6v. I completed the same process for the other headlight connector and came up with the same results.
As far as testing the flasher the way I did, I assumed that since the flasher is basically a switch that uses a resistor that I could test for resistance and should show some number greater than 1 at least.
I do have a Haynes manual and I've read it some, mostly for the suspension work you will see posted in the modifications to the truck but will have to go back and refer to it more with regards to the electrical system of the truck.
To answer your questions in order, the parking lights are also out, I have not got around to testing them yet.
The truck has both headlights, however, after replacing the first one with a new unit I stopped to check that it was operational before moving on to the second headlight. The new unit is a Sylvania H6054 Sealed Unit. That is when I discovered the issue. So I began searching for the issue. At first I thought maybe the female connectors were just clogged up with stuff so I used compressed air and contact cleaner to get any gunk out of them, then retested. Still had no low beam. So I unhooked the female connector, with the truck running and the headlight switch turned to the High Beam setting, placed the negative into the right post slot (Black Wire) and the positive into one of the other slots (I honestly can't remember if the top or the left was high beam). I was able to get a reading of 12v out of the high beam slot and then I switched the selector switch back to Low Beam in the cab and moved the positive lead from the multimeter to the last unchecked slot on the connector and only showed 0.6v. I completed the same process for the other headlight connector and came up with the same results.
As far as testing the flasher the way I did, I assumed that since the flasher is basically a switch that uses a resistor that I could test for resistance and should show some number greater than 1 at least.
I do have a Haynes manual and I've read it some, mostly for the suspension work you will see posted in the modifications to the truck but will have to go back and refer to it more with regards to the electrical system of the truck.
10-30-2018, 11:43 PM
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Your truck info needs to be in your SIGNATURE so it appears automatically with each post:
https://www.f150forum.com/profile.php?do=editsignature We need to know ALL the symptoms, maintenance & repair history, and all the features, options, & modifications so we can figure the best diagnostics for you, and the most-likely causes.The beam select is not part of the headlight switch.The beam select is a stomp switch on the floor - it has no indication what beam is selected. You can only tell by which beam comes on, and since your low beams never come on, the switch may NOT be changing to that setting.
No, it's basically a thermostatic circuit breaker wrapped in a heating element.Again: how did you come up with that value? 1 what? 1 microOhm? Or 1 MegaOhm?
The only way to test a flasher is under its normal load. If it has 12V going in, and the right number of normal bulbs with good grounds, and it doesn't flash - it's bad.
https://www.f150forum.com/profile.php?do=editsignature We need to know ALL the symptoms, maintenance & repair history, and all the features, options, & modifications so we can figure the best diagnostics for you, and the most-likely causes.The beam select is not part of the headlight switch.The beam select is a stomp switch on the floor - it has no indication what beam is selected. You can only tell by which beam comes on, and since your low beams never come on, the switch may NOT be changing to that setting.
The only way to test a flasher is under its normal load. If it has 12V going in, and the right number of normal bulbs with good grounds, and it doesn't flash - it's bad.
