Headlights not working

Tiny
SCOTT WUEST
  • MEMBER
  • 2003 CHEVROLET IMPALA
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 100,000 MILES
I replaced the daytime running light module and the headlight switch on my daughter's car and the headlights still do not work. What else should I try?
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Thursday, March 31st, 2011 AT 10:41 PM

30 Replies

Tiny
WRENCHTECH
  • EXPERT
It sounds like the headlight relay is not working. Here is a guide to help test the relay and the wiring diagrams for the headlights so you can see how the system works and the relay location as well:

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

Check out the diagrams (below). Please let us know what happens.

Cheers
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Thursday, March 31st, 2011 AT 11:05 PM
Tiny
JDL
  • EXPERT
Not trying to butt in, just a slow day. At the right headlamp assembly, check orange wire for voltage. Use a voltage tester, hot all the time. The pink wire and dark blue wires are grounds. If there is much voltage on the ground circuit, there is a ground problem. Yes, I realize saying there is a faulty ground, throws a pretty wide loop. Use the headlamp switch, not automatic lamp control.
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Thursday, March 31st, 2011 AT 11:24 PM
Tiny
LVZNLO
  • MEMBER
I had this problem the relay fixed it great post BTW.
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Thursday, August 2nd, 2018 AT 2:07 PM
Tiny
MELARCHIVALS
  • MEMBER
  • 2003 CHEVROLET IMPALA
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 195,000 MILES
Both low beams stopped working suddenly. The high beams work.

I checked both fuses (located in the fuse box under the hood, passenger side) they were good. Both light assemblies were removed and the connectors and bulbs were checked for damage. The bulbs were clean, intact, and looked brand new. The connectors were also clean and in good shape.

A local parts dealer suggested checking the Headlamp Relay, (which I tried to do on site but could not locate it. I later discovered is located on the back of the fuse panel on the driver's side, the interesting note here is that although all that I did while parked at the parts dealer was remove the fuse panel cover and then replace it when I could not see anything that looked like a relay. The low beams came on when I put the car in drive and then stayed on until I parked the car at home. On a whim, I put the car back into drive and the lights did not come back on).

After some reading, I went back to the fuse panel on the driver's side in an attempt to get to the relay. I was unable to do so (due to time and physical disability). However, with the cover off of the panel, I could hear the relay working when I used the key fob to unlock the trunk (at night, it will flash the lights two times, then keep them on for a few minutes). The relay clicks sounded clean. No sounds of sticking. Until I can get at the relay, I am assuming that it is good, as I have never had a problem with the low beams until now.

I have had the high beams cut out on some rare instances, but a click to low and then back again fixes that problem.

I have also had the turn signal fail from time to time but turning the hazards on for a second or two seems to correct that.

I am guessing it is the multi-function switch on the steering column.
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Thursday, August 2nd, 2018 AT 2:09 PM (Merged)
Tiny
SATURNTECH9
  • EXPERT
Sure sounds like a bad multi function switch from what your saying. Do you have a multi meter to do some testing?
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Thursday, August 2nd, 2018 AT 2:09 PM (Merged)
Tiny
MELARCHIVALS
  • MEMBER
Yes, I do.
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Thursday, August 2nd, 2018 AT 2:09 PM (Merged)
Tiny
MELARCHIVALS
  • MEMBER
Okay. After a fiasco at a local repair shop, in desperation I went through what I could get to again. Fuses and relays.

I found a relay that I had overlooked on the previous check (a driving light relay located in the box under the hood on the passenger side) replacing it did not change anything (I tried replacing it, because I could not remember how to check it). I did not find any loose connections anywhere. After two hours of pulling, checking, and putting back, I gave up and put everything back into place and reconnected the battery.

Went to move the car and the blasted things came on. I am hysterically relieved but not holding my breath, because I have not changed anything.

Still have the one relay on the back of the driver side fuse panel that I could not get to. I read somewhere that there is a tab that releases that so that it will drop down allowing access but I did not see it. I am physically limited, so I am not up for laying on the floor of the car and trying to reach for it. Although, by listening, it sounds like it is working (and must be since the lights are working now).

I did not get to any of the wiring behind the kick panel, which is where the multi-function switch wiring harness connector is located and I do not have the torx bits necessary for the steering column. (I am uncomfortable messing with the airbag anyway).
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Thursday, August 2nd, 2018 AT 2:09 PM (Merged)
Tiny
MELARCHIVALS
  • MEMBER
Something else that I have become aware of. The lights are working as DRL's (but not always) and, so far, they will not work at night. At night, it is high beams only.
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Thursday, August 2nd, 2018 AT 2:09 PM (Merged)
Tiny
LILSHEP2010
  • MEMBER
  • 2003 CHEVROLET IMPALA
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 145,000 MILES
I have the LS model and one headlight will not turn on. It has got 12.5 volts coming out of the plug that plugs into the headlight and the bulb is brand new. Any ideas or suggestions?
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Thursday, August 2nd, 2018 AT 2:09 PM (Merged)
Tiny
JDL
  • EXPERT
How about the ground?
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Thursday, August 2nd, 2018 AT 2:09 PM (Merged)
Tiny
MELARCHIVALS
  • MEMBER
Okay. Gave up and took it in to the shop. The tech's there told me when I picked it up that there was a code pointing to the multi-function switch. Something along the lines of a "random malfunction." I did not think to check the computer, although the code is no longer there and my book for the reader that I have, does not list a code for that particular message.
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Thursday, August 2nd, 2018 AT 2:09 PM (Merged)
Tiny
JDL
  • EXPERT
Just to add, voltage to the headlamps is hot all the time. On/off, high/low beam is controled on the ground circuit. In the diagram, the top wires going into the lamp assembly is voltage, bottom wires are ground.
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Thursday, August 2nd, 2018 AT 2:09 PM (Merged)
Tiny
LILSHEP2010
  • MEMBER
I replaced the ground. Before I did the plug had 11 volts. After it was 12.5.
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Thursday, August 2nd, 2018 AT 2:09 PM (Merged)
Tiny
LILSHEP2010
  • MEMBER
So the dark blue wire is a ground?
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Thursday, August 2nd, 2018 AT 2:09 PM (Merged)
Tiny
JDL
  • EXPERT
Dark blue wire is ground for low beam. If there is any voltage to speak of on that dark blue wire, with headlamp switch on, the ground is faulty. Is low beam the problem?

The dark blue wire goes to dimmer switch, from dimmer, a light blue wire goes to headlamp relay. When the relay is energized, low beam goes to ground.
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Thursday, August 2nd, 2018 AT 2:09 PM (Merged)
Tiny
SPEEDRACER30
  • MEMBER
  • 2003 CHEVROLET IMPALA
  • 90,000 MILES
My headlights quit working in my car. I replaced fuses, relays and headlight switch. Would both bulbs quit at once? Replaced fuses, relays, and headlight switch.
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Thursday, August 2nd, 2018 AT 2:09 PM (Merged)
Tiny
LILSHEP2010
  • MEMBER
The low beam is the problem. It flickers for about five to ten seconds then totally turns off and never comes back on. I replaced the ground that connects to the plug that connects to the bulb.
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Thursday, August 2nd, 2018 AT 2:09 PM (Merged)
Tiny
RIVERMIKERAT
  • MEMBER
Check the ground for the headlight relay and for the headlights.
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Thursday, August 2nd, 2018 AT 2:09 PM (Merged)
Tiny
JDL
  • EXPERT
The headlamp switch/dimmer switch/headlamp relay/BCM, plus the wiring circuit itself on that circuit.
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Thursday, August 2nd, 2018 AT 2:09 PM (Merged)
Tiny
LILSHEP2010
  • MEMBER
So which one is it?
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Thursday, August 2nd, 2018 AT 2:09 PM (Merged)

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