1994 Buick LeSabre Owner's Manual - Page 128

Air entering the car will be evenly split between the floor outlets and the outlets near the windshield. Rear Window Defogger (Option) The lines you see on the rear window warm the glass. Press the button to start warming your window. The blower speed will be controlled automatically. You can choose another fan speed by pushing the HI or LO buttons. Defrost This setting directs most of the air flow toward the windshield. Use this when there is fog or ice on the windshield. After 10 minutes, it will go off by itself or, pressing the button again during the heating cycle will shut it off. If you need additional warming time, push the button again. If you have the heated outside rearview mirror option, the mirror will be warmed when the rear defogger is on. Defrost will work better if any ice and snow is cleared from the hood and the air inlet area between the hood and the windshield. Blower speed will be controlled automatically. You can choose anotherspeed by pushing the HI or LO buttons. I NOTICE: Scraping the inside your rear window could of cut and damage the heater. Your warranty would not cover this damage. Don't put decals there, you might haveto scrape themoff. 126