2008 GMC Envoy Owner's Manual - Page 350

Backglass Wiper Blade Replacement 3. Rotate the wiper blade assembly, and pull it off of the wiper arm. Hold the wiper arm in position and push the blade away from the wiper arm. 1. Lift the wiper blade assembly up and out of the park rest position. 2. Pull the wiper blade assembly away from the backglass. The backglass wiper blade will not lock in a vertical position, so care should be used when pulling it away from the vehicle. 4. Replace the wiper blade. 5. Return the wiper blade assembly to the park rest position. 5-56