2003 GMC Sierra 1500 Pickup Owner's Manual - Page 183

a A/C (Air Conditioning): Press this button to manually turn the air-conditioning system on or off. When the system is selected, or in AUTO mode the system will automatically begin to cool and dehumidify the air inside of your vehicle. If you select air conditioning off while in front defrost, or defog mode the air conditioning off symbol will flash to let you know this is not allowed. @) (Front Defrost): Press the front defrost button to defrost the windshield. The system automatically will control the fan speed if you select defrost from AUTO mode. If the outside temperature is 40°F (4°C) or warmer, your air conditioning compressor will automatically runto help dehumidify the air and dry the windshield. Rear Window Defogger The lines you see on the rear window warm the glass. The rear window defogger uses a warming grid to remove fog from the rear window. You may notice a slight change in engine performance when the air-conditioning compressor shuts off and turns on again. This is normal. turn the air conditioning off, this symbol will appear on the display. When the air conditioning is selected or in AUTO mode, the system will run the air conditioning automatically. ?% (Air Conditioning Off): When you @ (Rear): Press this button to turn the rear window defogger on or off. An indicator light in the button will come on to let you know that the rear window defogger is activated. The rear window defogger will turn off approximately 10 minutes after the button is pressed. If you need additional warming time, press the button again. If you vehicle is equipped with heated mirrors this button will activate them. 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 defogger and the repairs would not be covered by your warranty. Do not attach a temporary vehicle license, tape, a decal or anything similar to the defogger grid. Defogging and Defrosting You can use either defog or front defrost to clear fog or frost from your windshield. Use the defog mode to clear the windows of fog or moisture. Use the front defrost button to defrost the front windshield. +3(Defog): Use this setting to clear the windows of fog or moisture. Press the mode button to select this setting. This setting will deliver air to the floor and windshield outlets. 3-28