2001 GMC Savana Van Owner's Manual - Page 148

A/C: This setting is used for normal cooling on hot days. It cools outside air and directs it through the instrument panel outlets. BI-LEVEL A/C: This setting divides airflow between the heater floor vents and instrument panel vents. The air conditioning compressor will cycle continuously in this setting as long as the outside air temperature is warm enough to activate the compressor. VENT: This setting directs air through the instrument panel vents. HEAT: This setting directs air through the heater floor vents. It is useful for cold weather. HEAT/DEFOG: This setting divides airflow between the heater floor vents and the windshield. In the blended position, the air conditioning compressor is automatically activated to dehumidify the air. DEFROST: This setting directs air through the windshield defroster vents. It is useful when you have fog or ice on the windshield. Rear Heater (Without Air Conditioning) (If Equipped) If you have a rear heater (without rear air conditioning), the control is located on the instrument panel. To increase and decrease the flow of heated air to the rear floor vents, turn the thumbwheel marked REAR HEAT to the speed you want. The thumbwheel has three speed positions. To increase the flow of heated air, turn the thumbwheel toward HIGH. To turn the fan off, turn the control to OFF. 3-4