Hello,

I have a 2004 Sunfire. The headlight went dim about a week ago. So far I have:
*Switched bulbs, and the bad bulb works on the good side, and the good bulb doest work on the bad side.
*Checked fuses, they are fine. The bad headlight actually stays on when I pull the fuse, though the good side turns off
when I pull its fuse (that shocked me).
*Cleaned the main ground under the battery.
*Cleaned the ground under the battery tray.
*Ran a voltmeter from the battery through the ground and it was 12 volts, so I'm guessing that it is not the ground.
*Ran a test light on the connector, and it is not getting power.

#1 - If the ground is good, what else can it be?
#2 - Is there a relay in the headlight system, or is it just the dimmer switch (or stalk on the steering column)?
#3 - How would I go about checking the dimmer switch?
#4 - Why would the headlight stay on when the fuse is pulled?

Any other advise would be greatly appreciated.

Thank you all in advance for your help.

Dimmer switch does nothing on that. you have a crossed wire that is shorting it out. Check all the wires from the headlight for cuts that maybe grounded.
I have an issue similar. My dr front turnsignal doesn't turn on with the headlights but the light is on. on the dash.
when you use the turn signal it blinks real fast and the power output is near dull. changed the bulb same thing.
My issue was the rear taillight wiring had a cut in it that grounded an basicly killed it for a day. it works now. But check front and back they are connected.

Update,

There is now a fast clicking noise in the fuse box inside the car after the car starts and I take the e-brake off. I think that is when the Daytime Running Lights come on.It only lasts for a second, but I got shocked a little when I tried to pull the fuse while it was doing it. It doesn't blow the fuse though. If I pull the fuse for the bad headlight it doesn't do it.

LOL I had the same problem sorry to laugh. If you tryed to disable your DRLs and something is not completely correct then it will start to clicking... I went to the dealer and it was my DRL relay thats right their at the door panel for the fuses. The parts guy at GM gave me a new one for free... But it kept doing it then I investigated everything and it was the ground for my DRLs was loose


5 seconds to find another street...

Still no luck, I dread taking it to the stealership.

Does anyone know why my headlight would stay on if the fuse was pulled? I can pull both fuses and the bad headlight stays on, its just really dim.

Ok, I bugged my fiance for a few reasons of why it could be.

He's stuck on the ground issue.

IF NOT that...

Bad harness?
Power back feeding to the light from another system, most likely another light?
Double check everything and make sure it's a correct bulb if you've changed it recently?

Hopefully something along those lines helps out... He's racked his brain and that's about all he can come up with!

Update,

It's not the relay, I switched that out for a known good one, and it did the exact same thing. So now I am down to:

-Ground?
-Broken Wire from power coming in?
-Why does headlight work when fuse is pulled? (Crossed wires somewhere?)
-VooDoo!

So you all know, this car has no modifications, no DRL bypass, no nothing, just regular oil changes and such.

check your mail.
then your wires. Let us know.


01 cav w/01 3400 gam gt 4t45e

Update:

My car is completely disassembled in my garage. The dashboard is off, the front wiring for the lights have been stripped, and I have not found any breaks. I am still in the process of testing wires, but nothing is visually off.

I have one problem, and that is that the wire loom that connects to the lights up front runs to a connector that is under the battery tray and I have no way of pulling that through to the front of the car without removing the windshield wiper fluid reservoir. The loom is pinned between the frame and the reservoir and will not pull through. I have ohmed the connectors on the bad side to the connector, and there is no resistance on the two wires that go through to the connector, which I believe are the wires that eventually lead to a ground.

I am going to be pulling the fuse panel out tomorrow to take a look at the wires behind it to see if any of them are crossed or touching, or out.

So for now I am down to:
*Broken or crossed wire.
*Faulty Body Control Module.
*Faulty Headlight dimmer switch (stalk on steering column).

I will be updating this thread until I find the cause of the problem or I take it to the stealership. If I do take it somewhere to get it fixed I will post what the cause was so that others with the same problem may be able to fix it themselves or at least know what may be wrong before they take it somewhere to get it fixed.

Nick

did you get the diagram I sent you ?


01 cav w/01 3400 gam gt 4t45e

That section of the front harness that goes down near the washer bottle is usually where you'll find a corroded wire or splice. Can't remember exactly, but it's probably either a pink or dark blue wire your looking for. you don't have to remove the washer bottle, just the 2 10mm bolts, one just below where the left headlamp sits, the other is down near the lower rad support (you have to undo the front part of the inner fender to get to this one) There is a gound on the harness bolted to the body just under the battery tray, this one is the hardest ont to get to, but still not too bad. Unplug your harness and washer pump and you should be able tp pry the washer bottle over (carefully!) enough to remove the harness. I know this sound like a lot, but it really isn't. Once the harness is out, you should be able to find your problem fairly easily, look for the magic green powder!! Hope this helps.

Framescraper got it!

Well, I mean that I was coming to post that it is fixed and what he said is correct. It was a corroded wire next to the windshield wiper fluid reservoir. It was all green and corroded. It was actually the same wire that I had found another break in earlier in my attempts. Hope this helps anyone else that has the problem. Just follow the voltmeter back until you find it!

Nick

I guess you didn't search too long. I posted this problem a little while ago. The fact that the harness is sandwiched in between the washer fluid bottle and the frame is a big flaw in assembly. Techline shows the harness is supposed to go in the space between the radiator and the header panel support. It pinches the harness so tight it breaks after a few years. This should really be a mod everyone does. Take the bottle off, unplug the harness from the big connector, the ground under the battery box, and the washer pump and move it around the other side of the header support.

Thank you Charlie,

For pointing out that I might not have found every single piece of information available on the internet about a headlight being dim. I bow to your absolute genius.

Why is it that every post on an internet forum has to get flamed by some a$$hole because they want attention.

Also, if you recently posted something about this, why is it that I didn't find anything about it when I searched the web or this site? Did it have to do with a dim headlight? Because my problem was not about a headlight out if thats what your post was on.

Lastly, I have to think that this thread is a very complete overview of things that could be causing a headlight malfunction. Most other threads that I found only focused on one or two aspects of what the problem should be, as in a ground or a relay. This thread includes every major aspect of the headlight system in our cars. There are no other things that could cause a dim headlight than what is listed here. This may as well be a sticky.

First, let me apologize. I did not make that remark to flame, cause angst, or put down. I am here both to help others and to pick other's brains for my own purposes. I don't expect anyone to comb the site for every piece of information (not without some Ritalin anyway). Yes thank you, I am an absolute genius but am certainly not perfect. I had just pointed out that a recent discussion was made on the subject of corrosion and damage to the front wiring harness due to it being pinched in between the washer fluid bottle and the many symptoms it may cause including at least three posts on dim headlights. Excuse me for making a point. Have a nice day.