WARNING: This page is about a different car, the 2003 Oldsmobile Bravada, 2003 GMC Envoy XL, 2003 GMC Envoy, and 2003 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
Remove the bolt that retains the seat belt upper anchor to the body.
Remove the garnish molding from the vehicle.
Fig 1: Garnish Molding - Body Side Window - Front (TrailBlazer EXT & Envoy XL)