WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
Clean the mounting location on the windshield using a clean lint free cloth with isopropyl alcohol.
Install the rain sensor (1) to the windshield.
Fig 1: Rain Sensor & Retaining Ring
Courtesy of GENERAL MOTORS CORP.
Connect the electrical connector to the rain sensor (1).