WARNING: This page is about a different car, the 2003 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Radio/Audio System Schematic Diagram (Radio - U1P And UC6)
Courtesy of GENERAL MOTORS CORP.
Fig 2: Radio/Audio System Schematic Diagram (Radio - U1P And UC6 With UZ6 Amplifier)
Courtesy of GENERAL MOTORS CORP.
Fig 3: Radio/Audio System Schematic Diagram (Navigation Radio - U1A)
Courtesy of GENERAL MOTORS CORP.
Fig 4: Radio/Audio System Schematic Diagram (Navigation Radio - U1A And Remote CD Player)