WARNING: This page is about a different car, the 2007 Cadillac STS. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Radio Power, Ground, DLC and Audio Communications Schematic
Courtesy of GENERAL MOTORS CORP.
Fig 2: Speakers - w/UX8 Schematic
Courtesy of GENERAL MOTORS CORP.
Fig 3: Speakers (w/UY5) 1 of 3 Schematic
Courtesy of GENERAL MOTORS CORP.
Fig 4: Speakers (w/UY5) 2 of 3 Schematic
Courtesy of GENERAL MOTORS CORP.
Fig 5: Speakers (w/UY5) 3 of 3 Schematic
Courtesy of GENERAL MOTORS CORP.
Fig 6: Radio Antennas, Audio/Video Adapter Schematic
Courtesy of GENERAL MOTORS CORP.
Fig 7: Digital Radio Receiver - w/U2K Schematic
Courtesy of GENERAL MOTORS CORP.
Fig 8: Traffic Information Receiver Module (VICS) - Japan Only Schematic