WARNING: This page is about a different car, the 2008 Cadillac SRX. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: BCM Power, Ground, and Serial Data
Courtesy of GENERAL MOTORS CORP.
Fig 2: BCM Inputs and Outputs 1 of 4
Courtesy of GENERAL MOTORS CORP.
Fig 3: BCM Inputs and Outputs 2 of 4
Courtesy of GENERAL MOTORS CORP.
Fig 4: BCM Inputs and Outputs 3 of 4
Courtesy of GENERAL MOTORS CORP.
Fig 5: BCM Inputs and Outputs 4 of 4
Courtesy of GENERAL MOTORS CORP.
Fig 6: Rear Body Control Module References Export +UTA/UTB/UTC