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 to the door jamb switch.
Press inward on the door jamb switch (2) until fully seated in the hinge pillar.
Close the rear door.
Fig 1: Connecting Electrical Connector To Door Jamb Switch - Rear