GM Service Manual Online
For 1990-2009 cars only

The body control module (BCM) controls the remote rear compartment release operation. The BCM monitors input requests for trunk release operation from the trunk release switch through following components:

    • The CKT 1576
    • The RFA module (with AUO) through CKT 1807 (Class 2 Serial Data)

If the ignition switch is in the ACC or RUN positions, one of the following conditions must apply before the BCM will enable trunk release operation:

    • The transmission must be in PARK or NEUTRAL
    • The park brake must be applied

The BCM receives PRNDL status from the powertrain control module (PCM) through CKT 1807 (Class 2 Serial Data) and monitors park brake status from the park brake switch input on CKT 1134 at the BCM connector C2 terminal  A9. Voltage at connector C2 terminal A9 is pulled low when the park brake is applied. When the trunk release switch is activated, voltage at the BCM connector C2 terminal A9 is pulled low through CKT 1576 through the CKT 550 and ground at the G301 Ground Splice Pack. If the BCM determines that trunk release enable conditions are met, the BCM will ground terminal  B3 of the BCM connector C1, causing the trunk release relay to energize by allowing currrent to flow through the relay pull - in coil windings. When the trunk release relay contacts close, a path for current flow is created through CKT 56 to the rear compartment lid release motor, through CKT 750 to the G401 ground splice pack which energizes the motor causing the trunk latch to release.