1997 Oldsmobile Silhouette Owner's Manual - Page 202

Defogging and Defrosting To rapidly defrost the windshield, turn the temperature control knoball the way clockwise (to the red area) and turn the modeknob to DEFROST. Adjust the fan to the highest speed. Rear Window Defogger Press REAR (the light will glow) to warm the defogger grid on the rear window. To keep the windshield clear and bring inheated air through the heater ducts, turn the mode knob to DEFOG. When the temperature outside isabove freezing, the air conditioner compressor will run in these settings to help remove moisture from the air. Your vehicle is equipped with side window defogger vents located on the top of the instrument panel. For additional side window defogging, turn the mode knob to the BI-LEVEL setting and adjust the fan tothe highest speed. Aim the side vents on instrument the panel toward the side windows. For increased airflow to the side vents, close the center vents. The rear window defogger will turn off automatically after about 10 minutes of use. If you turn it onagain, the defogger will operate for about fiveminutes. You can also turn the defogger off by turning off the ignition or pressing the switch again. Do not attach a temporary vehicle licenseacross the defogger grid on the rear window.