Circuit/System Description
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2011 GMC Yukon XL, 2011 GMC Yukon, 2011 Chevrolet Tahoe, 2011 Chevrolet Suburban, and 2011 Chevrolet Avalanche. 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.