1998 GMC Sonoma Owner's Manual - Page 133

Optional Climate Control System Mode Knob The right knob on the control panel allows you to choose the direction of air delivery. OFF: This setting turns the system off. Some outside air will still enter the vehicle whenever the vehicle is moving forward. MAX A/C: This setting provides maximum cooling with the least amount of work. MAX A/C recirculates much of the air inside your vehicle so it cools quickly. This setting directs most of the air through the instrument panel vents and a small amount through the floor vents. 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. N C : This setting cools the air entering your vehicle and directs most of the air through the instrument panel vents and a small amount through the floor vents. +fl -bo BI-LEVEL A/C: This setting cools the air 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. entering your vehicle and directs it through the heater floor outlets aswell as the instrument panel outlets. / I VENT This setting directs most of the air through . the instrument panel outlets and a small amount through the floor outlets.The air conditioningcompressor is not working when VENT is selected. +. 3-3