GM Service Manual Online
For 1990-2009 cars only

Tonneau Cover Release Components

The tonneau cover release system consists of the following components:

    • Tonneau Latch
    • Rear Closure Release Switch
    • Tonneau Release Relay
    • Rear Defog/Trunk Release 40A Fuse
    • Body Control Module (BCM)

Tonneau Cover Release Controls

The tonneau cover may be released by commanding all the doors to unlock and by pressing the rear closure release switch.

Tonneau Cover Release Operation

The rear closure release switch is an input to the body control module (BCM). The BCM monitors to the signal circuit and when the rear closure release switch is pressed the signal circuit voltage goes low. When the BCM detects the drop in voltage in the rear closure release switch signal circuit, the BCM enables the Tonneau Release relay by applying battery voltage to one side of the relay control circuit and ground the other relay control circuit. This energizes the Tonneau Release relay coil which closes the contacts within the switch side of the relay and allowing voltage to flow through the relay to the tonneau latch control circuit and activating the tonneau latch.

The tonneau latch system will only be enabled when the doors are unlocked, the transmission is in Park or for vehicles with a manual transmission, when the vehicle is stationary.