Radio/Navigation System Schematics
WARNING: This page is about a different car, the 2008 Isuzu Ascender, 2008 GMC Envoy, and 2008 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
Fig 4: Audio Amplifier Power, Grounds & Premium Radio Low Level Audio Outputs w/o Rear Seat Audio Controls Schematic