2000 GMC Envoy Owner's Manual - Page 143

Rear Window Defogger The lines you see on the rear window warm the glass. The rear window defogger will stay on for five to seven minutes, then turn off. If you need additional warming time, turn it on again. You can turn the defogger off at any time by pressing the button. Do not attach a temporary vehicle license, tape or decals across the defogger grid on the rear window. NOTICE: Don't use a razor blade or something else sharp on the inside of the rear window. If you do, you could cut or damage the warming grid, and the repairs wouldn't be covered by your warranty. For best results, clear the window of as much snow or ice as possible before using the rear window defogger. To turn on the rear window defogger, find the button marked REAR with the defog symbol on the lower right corner of your climate control system. Press the button until the light in the switch comes on, then release it. It will only work if the ignition switch is turned to RUN. Pressing the REAR button on your climate control system will also activate your heated outside mirrors. This will help to keep ice, snow and condensation from collecting on your mirror surfaces. Ventilation System For mild outside temperatures when little heating or cooling is needed, use PANEL with the OUTSIDE AIR button enabled to direct outside air through your vehicle. Airflow is through the instrument panel outlets. Your vehicle's ventilation system supplies outside air to the inside of your vehicle when it is moving. When the vehicle is not moving, you can get outside air to flow through by selecting any mode and any fan speed. 3-6