2001 Chevrolet Impala Owner's Manual - Page 178

Ventilation System Adjust the direction of airflow by moving the vents. Ventilation Tips D Keep the hood and front air inlet free of ice, snow or any other obstruction (such as leaves). The heater and defroster will work far better, reducing the chance of fogging the inside of your windows. mode knob to LOWER and the fan to the highest speed for a few seconds before driving off. This helps clear the intake ducts of snow and moisture and reduces the chance of fogging the inside of your windows. objects. This helps air to circulate throughout your vehicle. D When you enter a vehicle in cold weather, adjust the D Keep the air path under the front seats clear of Your vehicle's flow-through ventilation system supplies outside air into the vehicle when it is moving. Outside air will also enter the vehicle when the air conditioning fan is running and the OUTSIDE AIR button is pushed. If the airflow seems very low when the fan is adjusted to the highest setting, regardless of the mode setting, your passenger compartment air filter (if equipped) may need to be replaced. See "Maintenance Schedule" in the Index. 3-8