RSE Outputs
WARNING: This page is about a different car, the 2009 Saturn Outlook, 2009 GMC Acadia, 2009 Chevrolet Traverse, and 2009 Buick Enclave. However, it is still accessible from the selected car via links, so may be relevant.
At minimum volume, the plus (+) and minus (-) audio signals are approximately half battery voltage, measured to vehicle ground. These audio signals are sent from the radio to the Infrared Module, most systems have a common minus (-) signal.