Circuit/System Description
WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
Pressing the liftgate switch closes a contact providing a ground for the rear closure handle switch open signal circuit. The body control module (BCM) will detect the voltage drop and command voltage to be supplied to the liftgate latch relay supply voltage circuit thus energizing the liftgate relay which provides voltage to the liftgate latch releasing the liftgate.