02 grand prix stereo

You would need to do some basic testing. Maybe wiring or a fuse.

That old it could be any number of things. Start with the basics first, fuses, wiring and then move onto components

If you're getting sound signal and power into the amp, the amp is issue. If there's power on the amp but no sound signal coming in from stereo, then there's an issue with stereo wirining from stereo, assuring stereo is turning on

The light for the display on these tended to burn out. I had to replace the one on my 2000 Grand Prix. Plus the stereo has "Theft Loc". If the feature is not turned off when you disconnect power to the stereo, either by disconnecting the battery or a fuse, the stereo will not work again until the security code is entered into the stereo. Hope that helps! Jim