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headlights flashing

Old Feb 9, 2014 | 11:44 AM
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From: Lexington. Mi.
headlights flashing

hey fellas, I have a 74 250 4 by 4 with the 390and after a short while my headlight start flashing sometimes will stay on for a while sometimes they wont, anybody ever have this problem before
 
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Old Feb 9, 2014 | 11:48 AM
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Seems to me I had that happen on a car I used to own many years ago, was either a headlight relay .... or a circuit breaker?
 
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Old Feb 9, 2014 | 12:11 PM
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No headlight relay on these trucks. There's a circuit breaker built in to the headlight switch. Check for shorted, pinched wiring or frayed insulation downstream. An overcurrent condition is causing the breaker to interrupt.
 
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Old Feb 9, 2014 | 12:24 PM
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are you talking about before or after the headlight switch
Originally Posted by fmc400
No headlight relay on these trucks. There's a circuit breaker built in to the headlight switch. Check for shorted, pinched wiring or frayed insulation downstream. An overcurrent condition is causing the breaker to interrupt.
 
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Old Feb 9, 2014 | 12:25 PM
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Downstream means after the source, toward the load. So, "after."
 
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Old Feb 9, 2014 | 12:48 PM
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I've had problems with the OEM switches not being capable of handling Halogen bulbs. But I can't remember what year they started using halogens. In those cases we wired a relay for high and another for low beams and solved the problem. I'm guessing by now they are making the headlight switches to handle the amps, so if it is just a weak breaker in the head light switch a new switch should probably fix it. Unplug one of your headlights and see if they stay on twice as long, that will tell you the switch is weak.
 
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Old Feb 9, 2014 | 12:49 PM
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FMC400, thanks, i will have ta look into that
 
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Old Feb 18, 2014 | 12:25 PM
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Originally Posted by EricJ
I've had problems with the OEM switches not being capable of handling Halogen bulbs. But I can't remember what year they started using halogens. In those cases we wired a relay for high and another for low beams and solved the problem. I'm guessing by now they are making the headlight switches to handle the amps, so if it is just a weak breaker in the head light switch a new switch should probably fix it. Unplug one of your headlights and see if they stay on twice as long, that will tell you the switch is weak.
hi Eric J, yeah I got around to looking at my truck last night and I did on plug one of the headlights and it did not Flickr at all so I'm going to invest in a new headlight switch considering that that is the factory switch that's in there, thanks for the suggestion
 
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