1994 Chevrolet Astro Owner's Manual - Page 135

If your vehicle hasrear air conditioning, setting iton LOW may enhance front A/C performance by allowing trapped refrigerant rear lines to in circulate. The system will only send cooled if the front system is on. It can still be air used to recirculate air, even if thefront system is off. Before using the rear air conditioning, open the windows clear the vehicle to of hot air.Close the windows when usingthe system. Rear Window Defogger If your vehicle hasthis option therear window will havelines running across the glass. These lines heat your window. For best results, clear the window of as much snow orice as possible before using the rear window defogger. To turn on the rear window defogger, find the switch marked REAR DEFOG on your instrument panel to the left of the steering column. Press the top of this switch until the light in the switch comes on, then release it. The rear window defogger will only work when the ignition switch is in the RUN position. You can turn the defogger off any time by pressing the bottom of the at switch. The defogger will shut itself off after several minutes that the so glass does not get too hot. the window still isn't clear, turn the defogger If on again. I NOTICE: Scraping the inside your rear window could cut and damage of the defogger. Your warranty would not cover this damage. And don't put decals there, you might have to scrape them off. I 3-7