Electrical

Check for voltage on two wires in the rear connectors. One should have 12 volts when the ignition switch is in the "run" position. The second one must have 12 volts all the time for the station preset memory and clock. If that one is missing, some models will be completely dead. On some, just the radio will be dead and the clock won't work or it will restart at 10:00 each time you turn it on.

GM cd players have a 100 percent failure rate, and since 1994 they won't let us buy radio service manuals or parts. They want to make the money on repairs from their grossly over-priced repair centers.