Circuit/System Description
WARNING: This page is about a different car, the 2011 GMC Acadia, 2011 Chevrolet Traverse, and 2011 Buick Enclave. However, it is still accessible from the selected car via links, so may be relevant.
The liftgate close switch and exterior liftgate handle switch are parallel circuits and provide a single input to the liftgate control module. When a switch contact closes and the voltage drops, the liftgate module detects the voltage drop and commands the liftgate to open.