Circuit/System Description
WARNING: This page is about a different car, the 2016 Buick LaCrosse. However, it is still accessible from the selected car via links, so may be relevant.
The exterior rear compartment lid release switch receives a signal from the body control module (BCM). When the exterior rear compartment lid release switch is activated the signal circuit is pulled to ground. The BCM applies battery positive voltage to the trunk release relay control circuit which energizes the relay. The trunk release relay is grounded at all times. With the relay coil energized, the relay switch contacts close allowing battery voltage to flow to the rear compartment lid release actuator causing the rear compartment lid to release.