No headlights

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aaronswink

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1990 c1500 5 speed 350. I have no power to headlights, have power going to switch and coming out of switch. No power at the headlight harness. Is there a relay that it runs through after the switch that could have went out? When I turn brights on there is no power to that wire either. I’m lost. All fuses under dash good. Need help. Only vehicle now
 

Remodelmaster

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1990 c1500 5 speed 350. I have no power to headlights, have power going to switch and coming out of switch. No power at the headlight harness. Is there a relay that it runs through after the switch that could have went out? When I turn brights on there is no power to that wire either. I’m lost. All fuses under dash good. Need help. Only vehicle now

When is the last time that your headlight switch was replaced?
 

Nad_Yvalhosert

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Continue chasing the wiring.
Get a Chiltons manual, look at the pinout charts and check for power at the firewall.
 

Schurkey

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Perhaps a moderator will move this thread out of "Engines" and into "Audio + Electronics".

Firewall connector corroded?

Broken ground wire(s) between headlights and chassis? (i.e., headlights are getting power, but don't light up 'cause they have no ground?)

Headlight bulbs burnt-out, perhaps due to over-voltage from a failed voltage regulator?

Someone converted the truck to underhood relays, and the relay power supply has failed? MOST folks that install aftermarket relays protect them with FUSES, which is CRAZY. They need to be protected with auto-resetting circuit breakers.
 
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aaronswink

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Continue chasing the wiring.
Get a Chiltons manual, look at the pinout charts and check for power at the firewall.
No power at the harness, everything I find online is not correct to my truck, does power run from main switch to bright switch?
 

aaronswink

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Perhaps a moderator will move this thread out of "Engines" and into "Audio + Electronics".

Firewall connector corroded?

Broken ground wire(s) between headlights and chassis? (i.e., headlights are getting power, but don't light up 'cause they have no ground?)

Headlight bulbs burnt-out, perhaps due to over-voltage from a failed voltage regulator?

Someone converted the truck to underhood relays, and the relay power supply has failed? MOST folks that install aftermarket relays protect them with FUSES, which is CRAZY. They need to be protected with auto-resetting circuit breakers.
Ground is good, put a test light on green headlight wire at connector no power. I can’t find the correct wiring diagram online
 

aaronswink

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Update. I jumped a wire from back of switch ( the one that gets power when I turn headlights on) to the headlight wire in the harness under hood, have power now but still no power to brights
 

Caman96

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Does a 1990 era have this fuse under hood?
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Schurkey

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Failure in the multi-function switch in the steering column?

1990 c1500 5 speed 350.

I can’t find the correct wiring diagram online
There may not be a link to a scanned manual for '90 in the sticky thread on this site; at least there wasn't a '90 manual originally.

May have to buy one from eBay. I've gotten several service manuals there, at advantageous prices.
 
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