Function Control Knob
When function control knob is in MAX A/C position, air inlet door vacuum control motor is at full vacuum, closing off outside air and admitting only recirculated air. See Fig 1. The panel/defrost door vacuum control motor is at full vacuum and panel/floor door vacuum control motor is at no vacuum, directing airflow to instrument panel A/C registers. A small amount of airflow from side window demisters will be present. The heater control valve is at full vacuum, preventing flow of hot coolant to heater core. Blended air temperature is not available. The A/C compressor will operate if outside temperature is above approximately 43°F (6°C). The blower motor is on.
When function control knob is in A/C position, air inlet door vacuum control motor is at no vacuum, admitting only outside air into passenger compartment. See Fig 2. The panel/defrost door vacuum control motor is at full vacuum and panel/floor door vacuum control motor is at no vacuum, directing airflow to instrument panel A/C registers. A small amount of airflow from side window demisters will be present. The heater control valve is at no vacuum, allowing flow of hot coolant to heater core. Blended air temperature is available. The A/C compressor will operate if outside temperature is above approximately 43°F (6°C). The blower motor is on.
When function control knob is in PANEL position, air inlet door vacuum control motor is at no vacuum, admitting only outside air into passenger compartment. See Fig 3. The panel/defrost door vacuum control motor is at full vacuum and panel/floor door vacuum control motor is at no vacuum, directing airflow to instrument panel A/C registers. A small amount of airflow from side window demisters will be present. The heater control valve is at no vacuum, allowing flow of hot coolant to heater core. Blended air temperature is available. The temperature can be adjusted to heat air, but air cannot be cooled below outside temperature. The blower motor is on. The A/C compressor will not operate.
When function control knob is in OFF position, air inlet door vacuum control motor is at full vacuum, closing off outside air from entering passenger compartment. See Fig 4. The panel/floor door vacuum control motor is at full vacuum and panel/defrost door vacuum control motor is at no vacuum, closing off airflow to defrost duct, side window demisters, floor duct and instrument panel A/C registers. A small amount of airflow from side window demisters will be present. The heater control valve is at full vacuum, preventing flow of hot coolant to heater core. The A/C compressor will not operate. The blower motor is off.
When function control knob is in PANEL/FLOOR position, air inlet door vacuum control motor is at no vacuum, admitting only outside air into passenger compartment. See Fig 5. The panel/defrost door vacuum control motor is at full vacuum and panel/floor door vacuum control motor is at partial vacuum, directing airflow to floor duct and instrument panel A/C registers. A small amount of airflow from side window demisters will be present. The heater control valve is at no vacuum, allowing flow of hot coolant to heater core. Blended air temperature is available. The A/C compressor will operate if outside temperature is above approximately 43°F (6°C). The blower motor is on. The center console blower motor (if equipped) is enabled.
When function control knob is in FLOOR position, air inlet door vacuum control motor is at no vacuum, admitting only outside air into passenger compartment. See Fig 6. The panel/floor door vacuum control motor is at full vacuum and panel/defrost door vacuum control motor is at no vacuum, directing airflow to floor duct. A small amount of airflow from side window demisters will be present. The heater control valve is at no vacuum, allowing flow of hot coolant to heater core. Blended air temperature is available. The temperature can be adjusted to heat air, but air cannot be cooled below outside temperature. The A/C compressor will not operate. The blower motor is on.
When function control knob is in FLOOR/DEFROST position, air inlet door vacuum control motor is at no vacuum, admitting only outside air into passenger compartment. See Fig 7. The panel/floor door vacuum control motor is at partial vacuum and panel/defrost door vacuum control motor is at no vacuum, directing airflow to floor duct, defroster duct and side window demisters. A small amount of airflow from side window demisters will be present. The heater control valve is at no vacuum allowing flow of hot coolant to heater core. Blended air temperature is available. The temperature can be adjusted to heat or cool air below outside temperature. The A/C compressor will operate if outside temperature is above approximately 43°F (6°C). The blower motor is on.
When function control knob is in DEFROST position, air inlet door vacuum control motor is at no vacuum, admitting only outside air into passenger compartment. See Fig 8. The panel/floor door and panel/defrost door vacuum control motors are at no vacuum, directing airflow to defroster duct and side window demisters. A small amount of airflow from side window demisters will be present. The heater control valve is at no vacuum allowing flow of hot coolant to heater core. Blended air temperature is available. The temperature can be adjusted to heat or cool air below outside temperature. The A/C compressor will operate if outside temperature is above approximately 43° F (6°C). The blower motor is on.