1993 Chevrolet Cavalier Owner's Manual - Page 112
1993 Chevrolet Cavalier Manual
Page 112 highlights
Comfort Controls & Audio Systems r ?ear Window Defogger (cow.) Don't use a razor blade or something else sharp on the inside of the rear window. If you do, you could cut or damage the warming grid, and the repairs wouldn't be covered by your warranty. Flow-Through Ventilation System Your Chevrolet's flow-through ventilation system lets outside air into the vehicle when it is moving. Outside air will also enter the vehicle when the heater or the air conditioning fan is running. 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 insideof your windows. 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 clear of objects. This helps air to circulate throughout your vehicle.