WARNING: This page is about a different car, the 2002 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Navigation System Schematics (Power, Ground, Components and GPS)
Courtesy of GENERAL MOTORS CORP.
Fig 2: Navigation System Schematics (Auxiliary RCA Video Jacks and Export Microphone)
Courtesy of GENERAL MOTORS CORP.
Fig 3: Navigation System Schematics (Domestic Microphone)
Courtesy of GENERAL MOTORS CORP.
Fig 4: Navigation System Schematics (TV Antenna Module)
Courtesy of GENERAL MOTORS CORP.
Fig 5: Navigation System Schematics (Vehicle Information and Communication System (VICS) Module)