WARNING: This page is about a different car, the 2005 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Schematic - Dash Integration Module (DIM) Power, Ground and Serial Data
Courtesy of GENERAL MOTORS CORP.
Fig 2: Schematic - Ignition Switch
Courtesy of GENERAL MOTORS CORP.
Fig 3: Schematic - DIM Inputs and Outputs - 1 of 3
Courtesy of GENERAL MOTORS CORP.
Fig 4: Schematic - DIM Inputs and Outputs - 2 of 3
Courtesy of GENERAL MOTORS CORP.
Fig 5: Schematic - DIM Inputs and Outputs - 3 of 3
Courtesy of GENERAL MOTORS CORP.
Fig 6: Schematic - Rear Integration Module (RIM) Power, Ground and Serial Data
Courtesy of GENERAL MOTORS CORP.
Fig 7: Schematic - RIM Inputs and Outputs - 1 of 2
Courtesy of GENERAL MOTORS CORP.
Fig 8: Schematic - RIM Inputs and Outputs - 2 of 2