I have a 2004 Grand Prix GT with the backlight problem that seems to be common on these cars. I've been researching like crazy for the past few days trying to get a good answer, and it seems like I keep running into dead ends. I tried posting in the electronics sub, but I didn't get any answers.
Anyway, I recently replaced the original stereo and door lock control panel with OEM replacements due to wear and tear on the originals. I upgraded from the single CD unit to the six-disc stereo and paid a dealer to unlock the new stereo with a Tech 2 scanner. Both have full functionality except for some reason I don't have the orange backlighting on the stereo, A/C panel, or the window/door lock panel anymore. I checked the fuses, but they are all intact. Logically, if it was working before I touched it (it was) and now it's not, the problem probably has something to do with something I handled. But what? Does a wire in the stereo control that backlighting in all three devices? Here's the other weird thing: it all seemed to light up fine when I first connected the replacement stereo. It took a second, but all the buttons eventually lit up with the amber backlight, but then by the time I finished installing the door switches, the backlight was not working anymore. I don't think the bulbs are burnt out because three different panels all stopped working at once. It's also weird that the A/C panel quit working because I didn't swap it, or even disconnect it. Last night I opened the dash back up to double-check all the wiring and it all looked good but all three panels still failed to light up, but the DIC and instrument cluster light up just fine. I am totally at a loss.
The only other thing I can think of would be some of the previous owner's custom sub/amp wiring may be to blame, but the lighting was all working before I did the stereo and switch swap, so that seems unlikely.
I just want to have some idea of what's going on so I don't pay out the nose for the dealer to fix it, especially if it's something easy I could do myself.
Thanks,
Dave