Headlights Won't Come On

Tiny
DONNERMAN28
  • CHEVROLET SILVERADO

Chevy, 2007 1500P/U, 130,000, V8. The headlights won't come on when the switch is turned. The daytime running lights seem to work fine. I have checked the fuses and they seem to be o.K. I have changed out the light switch but it did not help. I checked the voltage at the headlight plug and found approx. 9VDC. The lights themselves look o.K. And had good continuity. Can you help me please? I love this site!

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Saturday, August 18th, 2007 AT 10:19 PM

12 Replies

Tiny
JACK42
  • MEMBER

Hello,

It looks like there is a low and high beam control relay in the system. If this relay does not work the low beams will not light up. Here is a guide to help you test the relay make sure the headlight switch is on.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Here is a guide to show you how to check for power at any given point.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Here is the headlight wiring diagram along withe the fuse panel location and identification.

Please let us know what you find.

Cheers

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Sunday, August 19th, 2007 AT 7:48 AM
Tiny
DONNERMAN28
  • MEMBER

I will check the relay tonight when I get home. I checked the fuses for the lights in the relay box under the hood which checks o.K. All of the interior lights work along with the dimmer.

I checked the voltage at each position on the connector itself. The connector has a total of 11 terminals with a group of 4 and a group of 7. Two of the group of 4 have black wires which I believe to be neg (-). With the connector oriented with the four terminals on the right I found 12 volts on the far right terminal above the grounds and on position 3 (going from right to left) on the 4 terminals in the group of 7. I also found 12 volts in the middle postion in the group of 3 of 7.

I also checked the voltage for at the bulb connector once again and found 9.4 volts when the running lights were on but zero volts when the switch was turned for headlights? I am stumped!

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Sunday, August 19th, 2007 AT 6:43 PM
Tiny
JACK42
  • MEMBER

Power comes out of the switch and goes through the Daytime Running Lamp Module (behind left side of dash) be sure 12 volts is getting through that, then it goes through the dimmer switch (hi-low beam) check for 12 volts through that as well, get back to me.

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Monday, August 20th, 2007 AT 7:48 AM
Tiny
DONNERMAN28
  • MEMBER

I poked around the steering column looking for the terminal for the headlight dimmer switch and while poking I decided to try the relay test you have here and sure enough the lights started working when I replaced the relay! YA.

Needless to say I was puzzled before be now enlightened by 2Carpros

I figure there was a wire grounding out? I thought the wiring harness on the back of the switch assembly was a plug and when trying to pull it out a wire came loose? I didn't really tug on it I think it was loose in the connector and when the wheel was tilted it either.

Thanks guys!

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Monday, August 20th, 2007 AT 9:58 PM
Tiny
JACK42
  • MEMBER

Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help

Cheers

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Tuesday, August 21st, 2007 AT 7:54 AM
Tiny
MATTHEWPAUL27
  • 2006 CHEVROLET SILVERADO

I replaced my low beam head light on the drivers side and now none of my headlights work. The passenger side was working before the replacement and now nothing. I can hear the relay clicking over, have 12 volts at the fuse, and have a good ground on the connector. Unfortunately I can not find any schematics to trace back the power flow.

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Thursday, November 9th, 2017 AT 5:02 PM (Merged)
Tiny
SATURNTECH9
  • EXPERT
  • 31,189 POSTS

Did you try taking the new bulb out and see if the other headlight works?So you have less two ohms to ground on both ground to by head head lights?But no power to etier head light bulb?

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Thursday, November 9th, 2017 AT 5:02 PM (Merged)
Tiny
PETEBP
  • 2005 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 115,000 MILES

Chevy 2005 Silverado 2500 HD. Drivers low beam headlight is not working, changed 2 bulbs, passenger low beam is on. Hi beams work both sides, daytime running lamps work. Any ideas?

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Thursday, November 9th, 2017 AT 5:02 PM (Merged)
Tiny
CADIEMAN
  • MEMBER

Check the voltage at the bulb connector.

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Thursday, November 9th, 2017 AT 5:02 PM (Merged)
Tiny
FACTORYJACK
  • EXPERT
  • 4,230 POSTS

Each bulb is individually fused, by appropriately labeled fuses in the underhood fuse block. There is a high relay, and a low relay. If one side low beam works, and not the other, it still confirms the relay is working, and the body controller is controlling it. I would first check the left low beam fuse for one has power to it, and two is not open. If the fuse is open, replace the fuse. If the fuse blows, there is a short in the circuit from the underhood fuse block to the headlamp connector.

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Thursday, November 9th, 2017 AT 5:02 PM (Merged)
Tiny
TJBANSHEE
  • 2003 CHEVROLET SILVERADO

Electrical problem
2003 Chevy Silverado V8 Four Wheel Drive Automatic

my low beam head lights don't work, both suddenly stopped. Checked all fuses and relays and they are good, the switch is good because I can to turn the switch to on and I can use my high beams (the only way they work), even changed the bulbs. I can hear the relay click when I turn the switch to on. I have even swapped relays. Once again it is only my low beams. Thank you

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Thursday, November 9th, 2017 AT 5:02 PM (Merged)
Tiny
RACEFAN966
  • EXPERT
  • 5,123 POSTS

It sounds like you may have a combination switch problem. What I need you to do is place the head light switch in HEAD possition and unplug the combination switch do the low beams come on? If they do then you the dimmer switch may be at fault. Let me know what you find and we will go from there.

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Thursday, November 9th, 2017 AT 5:02 PM (Merged)

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