1994 GMC Suburban Owner's Manual - Page 140

Comfort Controls Flow-Through Ventilation System Your vehicle's flow-through ventilation system supplies OLltside 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, through the vehicle and out the rear air exhaust valves. Outside air will also enter the vehicle when the heater or the air conditioning fan is running, unless your optional air conditioner is in the MAX mode. For more information see "MAX Button" in this section. Ventilation Tips 0 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. When you enter a vehicle in cold weather, turn the blower fan to HI for a few moments before driving off. This helps clear the intake ducts of snow and moisture, and reduces the chance of fogging the inside of your windows. Keep the air path under the front seats clearof objects. Thishelps air to circulate throughout your vehicle. 0 0 3-2