1993 Pontiac Grand Am Owner's Manual - Page 107
1993 Pontiac Grand Am Manual
Page 107 highlights
Comfort Controls & Audio Systems I RearWindowDefogger (CONT.:) I Flow-ThroughVentilationventilation System Your Pontiac's flow-through system supplies outsideair into the vehicle when it is moving. Outside air will also enter the vehicle when the heater or the air conditioning fan is running. 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 coveredby your warranty 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, turn the fan control knob to HIGH for a few moments before driving off. This helps clear the intake ducts of snow and moisture, and reduces the chanceof fogging the inside of your windows. Keep the air path under the front seats clear of objects. This helpsair to circulate throughout your vehicle.