How do you replace the radio in a 2003 Cadillac deville?

To replace the radio in a 2003 Cadillac DeVille, start by disconnecting the negative battery cable to ensure safety. Carefully remove the trim panel around the radio using a trim tool, then unscrew the mounting screws holding the radio in place. Disconnect the wiring harness and antenna cable from the rear of the radio, then replace it with the new unit by reversing the process—connecting the wiring, securing it with screws, and reattaching the trim panel. Finally, reconnect the negative battery cable and test the new radio.