1993 Pontiac Trans Sport Owner's Manual - Page 121
1993 Pontiac Trans Sport Manual
Page 121 highlights
Comfort Controls & Audio Systems Rear Window Defogger (CONK:) Don't use a razor blade or something else sharp on the inside of the rear window.If you do, you could cutor damage the warming grid, and the repairs wouldn't be covered by your warranty. Flow-Through Ventilation System Your vehicle's flow-through ventilation system supplies outside air into the vehicle when itis moving. Outside air will also enterthe vehicle when the heater or the air conditioning fanis running. Ventilation Tips: Keep the hood and front inlet free air of ice, snow, or any other obstruction (such as leaves). The heater and defroster will work far better, reducing the chanceof fogging the inside of your windows. When you enter a vehicle in cold weather, turn the blower fan to HIGH 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. 120