WARNING: This page is about a different car, the 2003 Pontiac Aztek and 2003 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
Position the rear window all the way down.
Remove the outer belt sealing strip screw.
Pull the outer belt sealing strip from the rear door pinchweld flange.
Fig 1: Removing Rear Door Window Belt Outer Sealing Strip