1997 GMC Sonoma Owner's Manual - Page 119

Ventilation Tips 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, move the fan control 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. 0 Keep the air path under the front seats clearof objects. Thishelps air to circulate throughout your vehicle. You will find air outlets in the center and on the sides of your instrument panel. You can move the outlets to directthe flow of air, or close the outlets altogether. When you close an outlet, it will increase the flow of air coming out of any outlets that are open. Defogging and Defrosting On cool, humid days, use BLEND to keep the windshield and side windows clear. Use DEFROST to remove fog or ice from the windshield quickly in extreme humid or coldconditions. Turn the temperature knob clockwise and move the fan control toward HI. 3-5