in my grand prix the stock radio head unit works fine. The only thing, the lights, when i turn on the headlights the LCD light shuts off and the backlights dont light up. I checked the wiring and the wire that most harnesses call the lighting wire is a data wire on this radio so i figure its getting a signal to light up but it aint HELP

jeez, this is a tough one... I know that delco electronics are finicky and fail just for the sick ugly fun of failing. Bad bulb/LED inside the radio face. On my 98 Lumina, half the lights for the radio don't work!

In my sunfire the display was incredibly weak as soon as I turn the lights on.

It's probably not the lamp illuminating it, but a bad op amp or something in there not accepting the adjustable light level.

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Is it fine when the lights are not turned on?

the screen was fine till i turned the lights on, anyways, the "dimmer" wire seems to send some sort of signal to the radio screen to take its light power from the "illumination" wire. because when i disconnected it the screen stayed lit when i turned on the head lights. anyways, the illumination wire had no voltage period. I snipped it and connected it to the switched +12v that powers the radio and now the entire face lights, ok all the time but i will fix that by tapping into the heater controls. I have a feeling last year when crappy tire changed the fuel pump for my father and they fixed a wire on the ECM then may have broke this wire. Anyways, in my troubleshooting i busted the light for the screen!

as fire as sunfires go, the heater control lights in mine are dead (they got so hot before burning out that they melted the sockets. The shifter is also burned as well as half the instrument cluster. Im sure that alternator last year pumping out 18v was no help for the lights