headlights turning off and on while driving

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Old 04-12-2011, 12:20 AM
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headlights turning off and on while driving

My headlights have been acting really weird the last couple of days. First time I noticed it was when I had to drive to school and the headlights would shut off when i would turn on the blinker. Then they would come back on when I turned the blinker off. Really weird I know. Well tonight I had to use my fog lights to get back home because the headlights didn't even turn on. luckily I had upgraded my fogs to brighter lights and there were no cops. What's wrong with my headlights and or wiring system lol

Thanks!
 
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Old 04-12-2011, 02:49 AM
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258- Is it BOTH the high AND low beams, or just the low beams? It sounds like a broken wire going from the MFS (multi-function-switch) to the fuse junction box. The MFS is on the turn signal arm. Take the cover off below (between the steering wheel and the dash) the steering column and check the wire loom to see if you have damaged wires there.
 
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Old 04-12-2011, 12:49 PM
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Code, I haven't really looked at the wiring for headlights on our trucks, but I had a similar problem once upon a time in an old Mercury. I was driving to work one dark morning and the headlights went off, came back on, and repeated this behavior. I discovered a damaged wire (insulation worn that was letting the wire short to ground). This caused the headlight circuit breaker to trip. Then it would reset and the process would repeat.

I imagine worn insulation in the vicinity of the multi-function switch would present similar symptoms, rather than a "broken wire".

I'm not nit-picking here, but a broken wire is easy to spot. A damaged one may take some careful inspection.

- Jack
 
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Old 04-12-2011, 01:24 PM
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Jack,

Close, but the headlamps ( either the feed to the main headlamp switch or the individual L & R lows and high beams ) are on fuses, so if they blew, they would not work until the fuse is replaced. No more circuit breaker.

I would go out on a limb, and say the MFS itself ( the contacts in it ) could be the cause of the symptoms. If the contacts are a bit wonky in the MFS switch, turning a directional on could have an impact on them ( this is the contacts from the high / FTP to low operation ).

Try as you may, you are not going to out dumb post me, I'm the KING !!!
 
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Old 04-12-2011, 02:00 PM
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Doesn't stop me from trying, SSCULLY! (Thanks for setting me straight though.)

Seems the multi-function switch is the "root of a lot of evil", isn't it?

- Jack
 
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Old 04-13-2011, 04:47 AM
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Try as you may, you are not going to out dumb post me, I'm the KING !!!
You're the KING Steve, but not the KING of DUMB! That's my story, and I'm stickin' to it!
 
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Old 04-13-2011, 04:50 AM
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Originally Posted by JackandJanet
Doesn't stop me from trying, SSCULLY! (Thanks for setting me straight though.)

Seems the multi-function switch is the "root of a lot of evil", isn't it?

- Jack
Jack, when the auto manufacturers bought into the fuse makers business, they quite putting "breakers" in the headlight systems.
 
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Old 04-13-2011, 10:58 AM
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Originally Posted by code58
Jack, when the auto manufacturers bought into the fuse makers business, they quite putting "breakers" in the headlight systems.
Shows how "out of touch" I am, doesn't it? :o (I've actually never had any problem with headlights since that incident, so there was no reason to study the way they were wired. The circuit breaker seemed a good idea to me at the time. I at least had headlights for part of the trip.)

- Jack
 
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Old 04-14-2011, 03:44 AM
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Originally Posted by JackandJanet
Shows how "out of touch" I am, doesn't it? :o (I've actually never had any problem with headlights since that incident, so there was no reason to study the way they were wired. The circuit breaker seemed a good idea to me at the time. I at least had headlights for part of the trip.)

- Jack
Jack, that was kind of tongue-in-cheek, but probably more truth than fiction there. Seems like money motivates EVERYTHING anymore.
 


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