1998 Pontiac Grand Prix Owner's Manual - Page 167

Heating On cold days use LOWER.The system will bring in outside air,heat it and send to the floor ducts. it If your vehicle has an engine coolant heater, you can use it to help your system provide warm faster when it's air cold outside0°F (- 18°C) or lower. An engine coolant heater warms the coolant your engine and heating system uses to provide heat. See "Engine Coolant Heater" in the Index. Ventilation System Ventilation For mild, outside temperatures when little heating or cooling is needed, useUPPER with the A/C button off, to direct outside through your vehicle. air Your vehicle also has the flow-through ventilation system described later in this section. Defogging and Defrosting Your system has two settings for clearing the front and side windows.To defrost the windows quickly, use DEE To warm passengers while keeping the windows clean, use DEFOG. Adjust the directionof airflow by moving the louvered vents. Your vehicle's flow-through ventilation system supplies outside air into the vehicle when is moving. Outside it air will also enter the vehicle whenair conditioning the fan is running. 3-8