1994 GMC Suburban Owner's Manual - Page 143

Function Lever The upper lever on the control panel can be moved to three different heating functions. Vent (Left): Air comes out at the vents on your instrument panel and at your front side windows. 0 Heater (Center):Air comes out near the floor. This setting, along with a heat setting, is best for cold weather. Defrost (Right):This setting operatesthe defroster. Air comes out near the bottom of the windshield and at your front side windows. Use this setting, alongwith a heat setting, when you get fog or ice on the windshield. Placing the lever between positions sends air out both vents. Temperature Lever The lower lever on the control panel lets you select the temperature of the air flowinginto the passenger area of your vehicle. Move the lever right toward (+) for warmer air. Move the lever left toward (-) for cooler air. Fan Control Knob The knob on the right side of the heating system control panel controls the fan speed. The knob has four speed positions. To increase the air flow, turn the knob toward (+). To decrease the air flow, turn it toward (-). Electronic Heating/Air Conditioning System If your vehicle has air conditioning,your heatinghir conditioning system will look like this. 3-5