Circuit/System Description
WARNING: This page is about a different car, the 2013 Cadillac XTS. However, it is still accessible from the selected car via links, so may be relevant.
When the body control module (BCM) receives a request to open the trunk lid, the BCM will briefly apply B+ voltage to the rear compartment lid unlatch relay control circuit, which energizes the coil side of the rear compartment lid unlatch relay. The switch side of the rear compartment lid unlatch relay then closes, supplying B+ voltage to the rear compartment lid latch. The rear compartment lid latch then releases the trunk lid so that it may be manually raised to an open position.