1998 GMC Sonoma Owner's Manual - Page 132

Comfort Controls With these systems, you can control the heating, cooling and ventilation in your vehicle. Mode Knob The right knob on the control panel allows you to choose the direction of air delivery. Standard Climate Control System OFF: This setting turns the system off. Some outside air will still enter the vehicle whenever the vehicle is moving forward. VENT: This setting directs most of the air through the instrument panel outlets and a small amount through the floor outlets. /J +e +e +@ BI-LEVEL: Air is delivered through the heater floor outlets as well as the instrument panel outlets. II"l Fan Control The knob on the left side of the heating system control panel controls the fan speed. To increase airflow, move the knob to the right. To decrease airflow, move it to the left. 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. Move the knob to the right toward the red area for warmer air. Move the knob to the left toward the blue area for cooler air. + setting directs most of the HEATER: This ' warmed air through the heater floor outlets and some air through the windshield defroster outlets. e w BLEND: Airflow e + is divided equally between the ' heater floor outlet and the windshield defroster outlets. DEFROST This setting directs most air through the windshield defroster outlets and some through the heater outlets.