WARNING: This page is about a different car, the 2006 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Ground, Indicators, Messages and Power - Wiring Diagram
Courtesy of GENERAL MOTORS CORP.
Fig 2: Wheel Speed Sensors - Wiring Diagram
Courtesy of GENERAL MOTORS CORP.
Fig 3: Brake Pedal Signal and Traction Control Switch - Wiring Diagram