GM Service Manual Online
For 1990-2009 cars only

Rear Compartment Lid Release

The rear compartment lid can be released by operating the interior rear compartment lid release switch, pressing the exterior rear compartment lid release switch while having a valid key fob with you, or pressing the rear compartment release button on the key fob.

When the rear compartment lid release is operated, battery voltage is switched to the rear compartment lid release actuator.

Rear Compartment Lid Release System Components

The rear compartment lid release system contains the following components:

    • Rear Compartment Lid Release Switch -- Exterior
    • Rear Compartment Lid Release Switch -- Interior
    • Driver Door Switch Assembly (DDSA)
    • Valet Lockout Switch
    • Instrument Panel Cluster (IPC) with Driver Information Center
    • Instrument Panel Module (IPM)
    • Remote Control Door Lock Receiver (RCDLR)
    • Rear Integration Module (RIM)
    • Trunk Door Release Relay
    • Rear Compartment Lid Release Actuator (includes actuator and rear compartment lid ajar switch)

The RIM is the logic owner for the rear compartment lid release system. The decisions required to allow a rear compartment lid release are made in the RIM and it sends the request to release the lid. Other modules associated with this system are only used to report switch status or to operate the relay that controls the actuator according to requests from the RIM.

When the rear compartment lid release switch is operated, the DDSA detects the rear compartment lid release switch signal circuit connected to ground and sends a serial data message indicating the request has occurred.

The valet lockout switch is closed in the normal or nonvalet position. When closed it supplies positive voltage to the valet lockout switch signal input to the IPM and the garage door opener. When the valet lockout switch is open in the valet position, positive voltage will not be detected by the IPM and the garage door opener will not have positive voltage. This is the Valet Lockout position. The IPM sends a serial data message containing the status of the valet lockout switch. This time the remote control transmitter or the rear compartment release button on the driver door can not unlock the rear compartment.

The RIM takes these serial data switch reports, and any requests from the key fob transmitters, and decides whether the rear compartment lid can be opened. If the RIM decides the request is authorized, the RIM will send a serial data message requesting the release of the rear compartment lid.

The RIM, when requested by a serial data message, will ground the trunk release relay control circuit. This energizes the coil and operates the trunk release relay. The relay then feeds positive voltage to the rear compartment lid release actuator.

Indicator Operation

When the trunk is ajar the rear compartment lid ajar switch is closed. This grounds the rear compartment lid ajar switch signal circuit to the RIM. The RIM then reports the switch status with a serial data message. The message is read by the IPC and a TRUNK OPEN message is displayed by the driver information center (DIC).