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Blinking Headlights? need fix

Ricasmaduse

Ricasmaduse

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Oct 25, 2019
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Location
Anchorage, AK
My headlights have started flashing on and off High Beam and low.
first the low beam right headlight went out and all my headlights are brand new.
As I am in Alaska it is dark when i get to work and even darker when i get off.
1991 k5
Any ideas?
 
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Check the ground wire. I believe it is on the driver's side on the back of the core support. If they are all doing it, that is where I would start. Unscrew it. Clean the all metal surfaces.
 
Its doing this even when parked. Radiator core support? Behind Grill?
also thought maybe bad relay but i looked behind glove box and couldnt find the relay?
Is it in that white box???
 
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1991 ground looks good found relay on firewall engine side looks like cut wire but have no idea were its supposed to go?

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I feel your pain. Watching this closely—having errant electrical issues as well.
 
I could be wrong as I have not owned that year, but that should be the fuel pump relay. The "broken" wire is a test feed.
 
totally ok to add redundant grounds and see if the problem goes away. Bat to block, block to body, block to core support. 91 is grounded to a stud right next to the tstat housing.
 
It can also be the headlight switch. I had a switch with a bad feed. Are the dash lights blinking also? Tail and marker lights?
 
Some headlight switches have a circuit breaker inside that auto resets when it cools down. Might be something like that making it go on and off?
 
Older stuff did. I dont think a 91 would have it. But that would do it. Eileen's Corvette had that issue. Had to use a non breaker switch, it is all that is available now, and run those feeds to breakers and relays as the new switch would not carry the load.
 
I believe that @ktmoutfront gave good good information about the ground wires for the front light harness. My '90 needed the grounds cleaned up on it after I got it. The negative battery cable should also have a small wire coming off of it to the radiator support. The ground wires at the thermostat housing are partially for the fuel injection harness.
I would also check if the dimmer switch is adjusted properly, or if the rod activating has a problem. It should click positively from low to high beam. I have seen them be out of adjustment, but often the won't switch.
There isn't a relay for the headlights, and as posted, you found the fuel pump relay. I would recommend putting a relay system in it to take the load off of the headlight switch AND turn on all 4 headlights when on high beam. This is assuming that you have the 4 headlight front end. I liked how it helped mine out when I did it.
 
So that was the fuel pump relay. I just replaced the dimmer switch and same problem still. Im thinking this may be the relay if there is one but im not 100% havnt taken dash apart. Cleaned ground and still same i ordered another one of these switches but wont be here till thursday. And im still unsure its what i need. Would be cool to have all 4 light when brights are on.

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I assume that you know already, but that isn't a factory installed relay, especially for the starter.
Did you find a ground wire on each side of the radiator support for the headlights?
 
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