1999 Chevrolet Silverado 1500 Pickup Owner's Manual - Page 162

yellowblue Comfort Controls Standard Comfort Controls Mode Knob The right knob on the control panel allows you to choose the direction of air delivery. VENT: This setting directs the air through the instrument panel outlets. BI-LEVEL: Air is delivered through the heater floor outlets as well as the instrument panel outlets. The air flow can be divided between VENT and HEATER depending upon where the knob is placed between the settings. HEATER: This setting directs most of the warmed air through the heater floor outlets and the rest of the air is divided between the windshield defroster outlets and the side window defroster outlets. BLEND: Airflow is delivered through the heater floor outlets, the windshield defroster outlets and the side window defroster outlets. The air flow can be divided between HEATER and DEFROST depending upon where the knob is placed between the settings. DEFROST: This setting directs most air through the windshield defroster outlets, side window defroster outlets and some through the heater outlets. Fan Knob The knob on the left side of the heating system control panel controls the fan speed. To increase airflow, turn the knob clockwise. To decrease airflow, turn it counterclockwise. To turn the fan off, turn the knob counterclockwise to OFF. Temperature Knob The middle knob on the control panel lets you select the relative temperature of the air flowing into the passenger area of your vehicle. Turn the knob clockwise toward the red area for warmer air. Turn the knob counterclockwise toward the blue area for cooler air. 3-2