2000 GMC Safari Owner's Manual - Page 153

Heating On cold days, use HEATER with the temperature knob in the red area. Outside air will be brought in through the floor outlets. The heater works best if you keep your windows closed while using it. If you use the optional engine coolant heater before starting your engine, your heating system will produce warmer air faster to heat the passenger compartment in cold weather. See "Engine Coolant Heater" in the Index. Ventilation System For mild outside temperatures when little heating or cooling is needed, use VENT to direct outside air through your vehicle. Air will flow through the instrument panel vents. Your vehicle's flow-through ventilation system supplies outside air to the inside of your vehicle when it is moving. With the side windows closed, air will flow into the front air inlet grilles at the base of the windshield, through the vehicle and out the rear air exhaust valve. Outside air will also enter the vehicle when the heater or the air conditioning fan is running. Defrosting Use DEFROST to remove fog or ice from the windshield quickly in extremely cold conditions. The temperature knob should be in the red area and the fan control toward high. The air conditioning compressor may operate in this setting to dehumidify the air. The BLEND setting is useful for cold weather with a large number of passengers or very humid conditions to help keep the windshield clear. 3-6