OnStar Wiring Schematics

WARNING: This page is about a different car, the 2011 GMC Sierra, 2011 GMC Cab & Chassis Sierra, 2011 Chevrolet Silverado, and 2011 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Module Power, Ground And Serial Data Wiring Schematic

Courtesy of GENERAL MOTORS CORP.

Fig 2: Communication Signals And Controls Wiring Schematic

Courtesy of GENERAL MOTORS CORP.