WARNING: This page is about a different car, the 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Identifying Data Link Connector Terminals
Courtesy of GENERAL MOTORS CORP.
Fig 2: Identifying Door Module (Driver) Harness Connector C1 Terminal
Courtesy of GENERAL MOTORS CORP.
Fig 3: Identifying Door Module (Driver) Harness Connector C2 Terminal
Courtesy of GENERAL MOTORS
Fig 4: Identifying Door Module (Driver) Harness Connector C3 Terminal
Courtesy of GENERAL MOTORS CORP.
Fig 5: Identifying Door Module (Driver) Harness Connector C4 Terminal