One problem related to sun roof has been reported for the 2004 GMC Envoy. The most recently reported issues are listed below.
On 3 separate occasions sun roof stuck in an open position. Dealership replaced the sun roof motor. This provided a temporary solution. Also, at 6,000 miles, severe and uncontrollable vibration occurred in the entire body of the vehicle when the rear windows were opened. Vibration occurred when the vehicle's speed exceeded 55 mph. Dealership representative indicated after test driving the vehicle that the vibration was normal, and only one rear window should be opened at a time. Consumer felt the vibration was caused by a design flaw in the rear windows.