WARNING: This page is about a different car, the 2003 Pontiac Sunfire and 2003 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
Connect the electrical connector.
Install the switch to the IP carrier.
Press the switch until the retaining tabs are fully engaged.
Fig 1: Installing Retaining Tabs For Rear Compartment Lid Switch