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Over the weekend, I noticed my door chime going off constantly any time the door was open. Previously, I think it would only do this if the key was left in the ignition, or the headlights were left on.
This morning I went to start up the car, and somehow the headlights had popped themselves up, and now will not do down. The lights themselves turn off and on fine. I took a look at the motor fuses, and they looked fine. All exterior lights seem to be working. I kind of suspect a grounding issue, but I'm terrible with electrical stuff. Fwiw, I did pull the washer fluid tank yesterday. One of its mounting points was also securing a ground strap which was sandwiched between the washer tank's mounting tab and the frame. I moved it to be sandwiched between the nut and the mounting tab, since that seemed to be like it would be a more solid contact. Anyway, the grounding strap was connected to a harness leading to the ABS pump. Doesn't seem like it would be connected to the headlights at all, but I'll put t back when I get home from work.
Anyone have suggestions on what else I should look at?
Update. I took some time after work to clean up all the grounds I could easily reach in the engine bay, including cracking open the 2 little multi ground boxes behind the headlights to clean the inside contacts. Nothing looked too bad, just a bit of the white and chalky stuff here and there. I also checked every fuse in both boxes that had the word headlight on it.
Headlights still won't go down. I manually put them down with the little *****, started up the car, and they stayed down. I turned the headlights on, and they popped up as normal, but again refused to go down.
So, what would cause the headlights to get the OPEN/ON signal, the OFF signal, but not the CLOSE signal?
I replaced them with LED about six months ago. They've always operated normally with them in.
This behavior (not closing) is a known issue when the OEM headlight bulbs are replaced with HIDs or LEDs. Therefore, it seems nothing is particularly wrong with your car.
What's curious is what you mentioned regarding proper operation after they were replaced until this began to happen. By any chance your high beam bulbs are still OEM? If they are, there's a workaround: you would need to switch ON your high beams before turning off the headlights in order for them to close.
Could it be you've been using your high beams before, so this wasn't noticed?
As I pointed out, they've been working flawlessly for 6 months. I actually already tried the highbeam workaround thinking the same as you, but they still wouldn't go down.
I'm kind of suspecting the headlight door actuator control module...which is a pretty expensive part. I'm having trouble finding where the dang thing is located on the car though. haha
I also read that blowing fuse 6 on the inside box will disable the brake lights, but somehow still allow the turn signals to light up and prevents the headlights from going down? I'm hoping for that one personally.
I'm kind of suspecting the headlight door actuator control module...which is a pretty expensive part. I'm having trouble finding where the dang thing is located on the car though. haha...
It is expensive and not available from GM. But troubleshooting the problem will give you a better chance to find the culprit.
That's why I suggested to reinstall the OEM bulbs to test the closing operation. It's a simple thing and it will give you a solid starting point.
The module is installed behind the passenger headlight assembly, against the fender wall.
Yeah, I'm planning on looking at both tonight. I found some used ones in the $120 range, and a new reproduction unit for $200+. If I have to spend $200, I might use this as an excuse to get some RadioFlyers instead. haha
Well hell. I'm pretty sure it's the headlight control module. I replaced the headlight bulbs with stock bulbs to no effect, and that fuse I mentioned was intact.
Definite signs someone has been into the HCM though. As soon as I pulled off one of the harnesses, I noticed it was covered in dielectric grease. Cracking open the cover, I noticed part of the tar seal around the edge was improperly applied, and wasn't sealing about 3/4" of one of the sides. Surface components mostly look good, but the traces on the back of the board look terrible. Looking at the right side of the picture, you can see a wide area of corrosion that just about goes all the way across with some pop-corning of the board. (it's a little puffy and flaky there)
If my electrical skills weren't so limited, I'd try to solder a lead around it, but it looks like the corrosion is just marching its way through it at this point.
On a positive note, after cleaning the board a bit and fiddling with it, I no longer get the annoying constant door chime. I guess the malfunctioning HCM was telling my BCM that the headlights were on. I must have jogged something back into connecting.
Headlights won't go down/constant door chime
