courtesy lights arent turning on

quadkid · #1 10-23-2005, 10:15 PM

Hey guys, im new to the forums and like what ive been seeing. Should probly say that this is the first CAR ive had to work on, im more into trucks.

Well heres the problem. I have a 99 Grand Am GT coupe, and a couple days ago my interior lights decided to not come on when id shut the car off or open a door. At first i was blowing fuses too, but tracked the problem to a loose connection in the mirror lights. But i still have the problem of the lights not coming on. I can turn them on manually with the rotary switch, but they dont come on automatically like they should. I have gone through all the fuses and swapped a couple relays and nothing. The only thing ive done to the car is replace the headunit to a Kenwood unit. Could that have screwed it up somehow? I know its installed properly since this is probably the 10th one ive put in.

Is there a switch somewhere im missing? Is it a computer program screwup?

Thanks guys in advance.

boug0752 · #2 10-25-2005, 10:26 PM

Hey,
I have seen this problem with a friends 99 GT. After we spent quite a few weekends trying to identify the problem we were unable to figure the exact problem. He took it down to the dealership where they "said" they tracked it down to a computer issue. I have a hard time believing this as its only stupid interior lights. My suggestion would be to go to a TRUSETED dealership and see if they might have seen this before and give you a truthful answer.
Sorry I can't be more help to ya.

quadkid · #3 10-26-2005, 09:32 AM

Hey, thanks for the info, man. Anything helps.

xeroinfinity · #4 10-26-2005, 02:57 PM

Quote:

Originally Posted by quadkid

The only thing ive done to the car is replace the headunit to a Kenwood unit. Could that have screwed it up somehow? I know its installed properly since this is probably the 10th one ive put in.

Is there a switch somewhere im missing? Is it a computer program screwup?

Thanks guys in advance.

Well if you used a ground for the radio that is really a hotwire. Some of these wires appear to be neg- but when the headlights are on it becomes a pos+. Just a thought. You didnt say if u used a wireing harness kit or you just cut/plice.

quadkid · #5 10-27-2005, 12:39 PM

ah, sorry bout that. yeah, i used a wiring harness and followed the haynes and panasonic manuals to wire them it up. im positive theyre done correctly and there arent any loose wires or bad connections, everything is soldered and heatshrinked. but thanks for the response.

xeroinfinity · #6 10-28-2005, 01:32 PM

Quote:

Originally Posted by quadkid

ah, sorry bout that. yeah, i used a wiring harness and followed the haynes and panasonic manuals to wire them it up. im positive theyre done correctly and there arent any loose wires or bad connections, everything is soldered and heatshrinked. but thanks for the response.

I thought Kenwood has a wiring harness kit that just plugs in and play, that is if ur using the factory speakers. The bcm controls the interier lights. The short in the mirror could hav toasted somethiing. Heres the wiring diagram if u need it. Good Luck
courtesy lights wiring diagram

quadkid · #7 10-29-2005, 03:51 PM

wow, just read that i wrote panasonic, hah, my truck has a panasonic. but yeah, i got the unit from crutchfield and made up the wiring harness they give you to tie into the factory harness.

dumb question, but whats the BCM? is that like the interior version of a PCM? kinda still getting used to all this fancy car stuff, haha, not a fan of the 1000 idiot lights and warnings.

thanks again

boug0752 · #8 10-29-2005, 05:38 PM

Hey quadkid,
The BCM is the body control module. It controls most electrical functions that are not controlled by the ECU. You can think of it as the ECU for lights, power crap, and anything else that isn't directly related to the engine or at least this is what I believe it to be.
The only reason I've heard of this is because right now my power locks don't work and we were actually looking at the BCM thinking that that might need to be replaced by we narrowed it down enough to realize that that wasn't it.
Hope this helps...

quadkid · #9 10-29-2005, 08:00 PM

yeah, finally opened up my haynes manual and looked through it a little more in depth. they dont tell you much about the BCM though. I'm going to set up an appointment this week to have it tested. How much do they usually go for if it needs replacement and is there any reputable online dealer of them?

boug0752 · #10 10-29-2005, 08:10 PM

I think that the dealer told me that for a new BCM it was a couple of hundred. I can't quite remember though for sure!

quadkid · #11 10-29-2005, 08:12 PM

well i just checked gmpartsdirect and they have it for $150. i hope thats not the best price or ill shoot my foot

oh, and where the heck is this BCM? would be awesome if the manual told me, but they dont even give a rough location. is it under steering column, glove box, engine bay, etc etc?

tommy00gt1 · #12 10-30-2005, 04:11 PM

On my 2000 GT1, the BCM can easily be accessed by removing the glove box. You might aslso be able to see it by laying on the floor, and have a flashlight and look up under the glove box.
Mine is a black, plastic looking box....almost the length/width of a cd or dvd case; only a little thicker.
I recently disabled my drl's and alc, so I had to get to the BCM module. It was so much easier when I removed the glove box.
Not sure where it is on a '99, but I'd venture a guess and say it is the same as mine.

Tommy

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