Circuit/System Verification
WARNING: This page is about a different car, the 2010 Saturn Outlook, 2010 GMC Acadia, 2010 Chevrolet Traverse, and 2010 Buick Enclave. However, it is still accessible from the selected car via links, so may be relevant.
Ignition ON, headlamps, HVAC, and all accessories OFF, observe the scan tool Battery Current parameter. The reading should be between -3 amps and -25 amps, and change with the amount of current draw on the battery.