electrical problems in parts getter

Ellis Kinney · Feb 12, 2018

1981 Ford, F 100, 300 inch six. Totally stock. I have an electrical problem with the headlights. Dimmer switch on the floor. Running on low beam the headlights do just fine. When I switch to high beam, after about 5 to 7 minutes the lights begin to flicker and then go out. Switch back to low beam and all is ok. What should I look for? Thanks, Ellis

Mike Groom · Feb 12, 2018

Probably the dimmer switch itself,could have some corroded contacts.Cheap replacement item,easy fix,check Rock Auto or local parts store.

Gambles · Feb 12, 2018

One, of many things to check out would be the headlight switch itself. It would have a breaker in it that would open up if too many amps are going through it.
Also check the wiring harness that attaches to it. Quite often this harness is burnt and causes the headlight switch to open up.

dr sportster · Feb 12, 2018

My guess is dimmer switch . Down on the floor they get dirt and wetness in them.

mite-help · Feb 12, 2018

running 5-7 minutes before failure doesn't really sound like a short, but possible. my thought is the light switch. it has an automatic reset circuit breaker. could be weak, and extra draw of high beam pushes it over the edge.

Michael Soldan · Feb 12, 2018

I agree with you, a dimmer switch is not an expensive replacement,try cleaning all contacts and the ground first, if not a new switch, the last one I replaced was around $12.

leroy in ne · Feb 12, 2018

I agree with others on switch. I had 69 that would do that, it had single 7" head lights and the breaker got weak, installed a switch/breaker out of 1958 car in junk yard that used the dual 5" light setup, heavier breaker and end of problem as it was a direct bolt in switch with the same wiring plug.

sotxbill · Feb 12, 2018

headlight switch was notorious on that model for doing that. To much juice though the switch. Replacement switch's will do the same very quickly. Wiring in a relay solves the problem permanently.

Areo · Feb 12, 2018

I had a similar problem on my wife's '63 sedan. Found that the light switch
contacts would open intermittently. Apparently they weakened with time. Now
the point I'm making is that perhaps the high beams take more power than low
beams. In this case it might be the light switch rather than the dimmer switch.
Just another possibility, if you find it's not the dimmer switch.

Areo

UncleTom · Feb 12, 2018

Also check the connections on the starter solinoid on the fender for being clean and tight. Chased the same problem years ago.

jeffcat · Feb 12, 2018

GAMBLES. YES! change the harness too. Had the headlight switch in the dash go bad on my Ford Explorer. Switch was going bad. It also fryed the uniplug that snaps onto the back of the swith. Junk yard and cut out the harness from a vehicle with farless miles. You want to do lineman type connections and use heat shrink tubeing on everything. Was a sweat repair after that.

Steve@Advance · Feb 12, 2018

Yep, headlight switch.

And more prone to start flashing off and on when behind a cop or the Hells Angles! LOL

Hobo,NC · Feb 12, 2018

The headlight switch is feed direct battery power let that sink in... Its fed thru a fuse link but not independently fused till it gets to the switch... Your issue is with the switch...

MARK ROBKE · Feb 12, 2018

Turn on the lights on hi beam.Reach up under/behind dash and feel the switch,and see if it gets hot.Heat will be the enemy:bad connection.BUT,I bet it is the dimmer on the floor.Pull back the floor mat and feel for hot connections.I say dimmer because it only does it on high beam.The dash switch does not change from lo to hi beam.But high beam may draw more amperage,there by speeding up the problem. Mark.

electrical problems in parts getter

Ellis Kinney

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Mike Groom

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Gambles

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dr sportster

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mite-help

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Michael Soldan

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leroy in ne

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sotxbill

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Areo

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UncleTom

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jeffcat

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Steve@Advance

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Hobo,NC

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MARK ROBKE

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