WARNING: This page is about a different car, the 2003 Pontiac Aztek and 2003 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Body Control System Schematics (Power, Ground & Serial Data)
Courtesy of GENERAL MOTORS CORP.
Fig 2: Body Control System Schematics (Subsystem References)
Courtesy of GENERAL MOTORS CORP.
Fig 3: Body Control System Schematics (Door & Body Rear End References)
Courtesy of GENERAL MOTORS CORP.
Fig 4: Body Control System Schematics (Lighting References)