GM radios are designed to make owners have to go back to the dealer. We can no longer buy radio service manuals from GM and Ford. If your car has a separate amplifier it might not be turning off. You might find a used one at a salvage yard that you can try, but don't remove the radio. GM cleverly built the Body Computer into it to prevent owners from replacing them. If the radio needs repair, it will have to go through the dealer to one of their two grossly over-priced authorized repair centers. The typical bill with all of the dealer's add-on charges is $450.00.