Radio/Navigation System Schematics
WARNING: This page is about a different car, the 2008 Saturn Outlook, 2008 GMC Acadia, and 2008 Buick Enclave. However, it is still accessible from the selected car via links, so may be relevant.
Fig 2: Audio Amplifier Power, Ground, and All Audio Inputs - UQG, Front and Rear Audio Inputs - UQA/UQS
Fig 3: Audio Amplifier Power, Ground, and All Audio Inputs - UQG+UK6, Front and Rear Audio Inputs - UQA/UQS+UK6