Circuit/System Description
WARNING: This page is about a different car, the 2016 GMC Acadia, 2016 Chevrolet Traverse, and 2016 Buick Enclave. However, it is still accessible from the selected car via links, so may be relevant.
The body control module (BCM) monitors the window UP and DOWN request from the driver window switch. When the rear window UP or DOWN command is received, the BCM sends a signal to the appropriate rear window switch. The rear window switches continuously monitor the up and down signal circuits, if no function is being commanded, the signal voltage is at approximately B+ voltage. If the UP or DOWN function is commanded, the BCM signal voltage drops approximately 0.5 volts and the appropriate rear window switch will then command the window in the UP or DOWN direction.