2003 GMC Sierra 1500 Pickup Owner's Manual - Page 175

Climate Controls Temperature Knob The middle knob on the control panel lets you select the temperature of the air flowing into the passenger area. Turn the knob clockwise toward the red area for warmer air. Turn the knob counterclockwisetoward the blue area for cooler air. Mode Knob The right knob on the control panel allows you to choose the direction of air delivery. f;' (Vent): This setting directs the air through the instrument panel outlets. Fan Knob The fan knob on the left side of the control panel adjusts the fan speed. To increase airflow, turn the knob clockwise. To decrease airflow, turn it counterclockwise. To turn the fan off, turn the knob to the off position. If the fan is off, outside air will still enter the vehicle, and will be directed based on the position of the mode knob. The temperature can also be adjusted using the temperature knob. (Bi-Level): Air is delivered through the floor outlets as well as the instrument panel outlets. The flow can be divided between vent and flooroutlets depending upon where the knob is placed between the settings. (Floor): This setting directs most of the air through the floor outlets, and the rest of the air is divided between the windshield defroster outlets and the side window defroster outlets. +2 0 (Off): 3-20