Circuit/System Description

WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.

The interior rear compartment lid release switch receives a signal from the driver door module (DDM). When the interior rear compartment lid release switch is activated, the signal circuit is pulled to ground. The DDM interprets this and sends a GMLAN serial data message to the body control module (BCM) requesting the rear compartment lid be released. The BCM responds by applying battery voltage to the trunk release relay control circuit which energizes the TRUNK RELES relay. The trunk release relay is supplied with battery voltage 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. The rear compartment lid release actuator is permanently grounded at G401. When the rear compartment lid release actuator releases the rear compartment lid, the rear compartment lid ajar switch, which is internal the rear compartment lid release actuator, is supplied with ground which causes the trunk ajar switch signal circuit to be pulled low. The trunk ajar switch signal circuit is an input to the BCM. When the BCM receives a trunk ajar signal, a GMLAN serial data message is sent to the instrument panel cluster (IPC) requesting the TRUNK OPEN message be displayed on the message center.