1997 Ford Aerostar Owner's Manual - Page 66

Fan speed adjustment The left knob or upper left knob with the x is the fan speed knob. Rotate the x knob to the right to increase fan speed and increase the amount of air entering the vehicle. Four fan speed positions are available. Function selection Use VENT to bring outside air through the instrument panel registers. You can heat the air in this position by rotating the center knob into the red area. The air cannot be cooled below the outside temperature regardless of the TEMP knob setting. Select NORM A/C to get refrigerated outside air through the instrument panel registers. The NORM A/C position is used for cooling except when it is extremely hot or fast cooling of the vehicle is needed. Select MAX A/C for fast cooling and return to NORM A/C when you are comfortable. The MAX A/C position rapidly produces cool air to provide faster cooling of your vehicle. This is possible because cooler air is drawn from inside the passenger area and cooled again instead of using warmer outside air. Use of inside air makes the fan sound louder and is normal when using MAX A/C. You cannot adjust the air temperature when operating in MAX A/C. If the airflow is too cold, select NORM A/C and adjust the air temperature as desired. Airflow will be to the floor when FLR is selected. The air cannot be cooled in the FLR position but can be heated by rotating the TEMP knob into the red area. 63