Function Control
When MAX A/C is selected, recirculation door vacuum control motor is at full vacuum, closing off outside air and admitting only recirculated air. See Fig 1. 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. Heater control valve is at full vacuum, preventing flow of hot coolant to heater core. Air will be drawn from recirculated air inlet by blower motor. When temperature selection is in full COOL position, airflow will be diverted past heater core and then into passenger compartment through instrument panel A/C registers. Compressor will operate if outside temperature is above approximately 43°F (6°C). Blower motor is on. Auxiliary blower motor is enabled.
When VENT is selected, recirculation door vacuum control is at no vacuum, admitting only outside air into passenger compartment. See Fig 2. 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. Heater control valve is at no vacuum allowing flow of hot coolant to heater core. Temperature can be adjusted to heat air, but air cannot be cooled below outside temperature. Compressor will not operate. Blower motor is on. Auxiliary blower motor is enabled.
When PNL/FLR is selected, recirculation door vacuum control is at no vacuum, admitting only outside air into passenger compartment. See Fig 3. Panel/floor door vacuum control motor is at partial vacuum and panel/defrost door vacuum control motor is at full vacuum, directing airflow to floor duct and instrument panel A/C registers. Heater control valve is at no vacuum allowing flow of hot coolant to heater core. Temperature can be adjusted to heat or cool air below outside temperature. Compressor will operate if outside temperature is above approximately 43°F (6°C). Blower motor is on. Auxiliary blower motor is enabled.
When FLOOR is selected, recirculation door vacuum control is at no vacuum, admitting only outside air into passenger compartment. See Fig 4. 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. Heater control valve is at no vacuum allowing flow of hot coolant to heater core. Temperature can be adjusted to heat air, but air cannot be cooled below outside temperature. Compressor will not operate. Blower motor is on. Auxiliary blower motor is enabled.
When FLR/DEF is selected, recirculation door vacuum control is at no vacuum, admitting only outside air into passenger compartment. See Fig 5. 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. Heater control valve is at no vacuum allowing flow of hot coolant to heater core. Temperature can be adjusted to heat or cool air below outside temperature. Compressor will operate if outside temperature is above approximately 43°F (6°C). Blower motor is on. Auxiliary blower motor is enabled.
When DEF is selected, recirculation door vacuum control is at no vacuum, admitting only outside air into passenger compartment. See Fig 6. Panel/defrost door and panel/floor door vacuum control motors are at no vacuum, directing airflow to defroster duct, and side window demisters. Heater control valve is at no vacuum allowing flow of hot coolant to heater core. Temperature can be adjusted to heat or cool air below outside temperature. Compressor will operate if outside temperature is above approximately 43°F (6°C). Blower motor is on. Auxiliary blower motor is enabled.
When AUTOMATIC is selected, temperature control setting is manually set to desired setting. Recirculation door vacuum control motor is automatically controlled by EATC module, based on temperature setting. Mode door vacuum control motors are automatically controlled by EATC module, based on temperature settings. Heater control valve is automatically controlled by EATC module, based on temperature setting. Compressor is automatically controlled by EATC module, based on temperature setting. Compressor will not operate if outside temperature is below approximately 43°F (6°C). Blower motor is on. Blower motor speed is automatically controlled by EATC module based on temperature settings, but can be manually overridden. Auxiliary blower motor is enabled.
When OFF is selected, recirculation door vacuum control motor is at full vacuum, closing off outside air from entering passenger compartment. See Fig 7. Panel/defrost door and panel/floor door vacuum control motors are at no vacuum, closing off airflow to floor duct, and instrument panel A/C registers. Heater control valve is at full vacuum preventing flow of hot coolant to heater core. Compressor will not operate. Blower motor is off. Auxiliary blower motor is disabled.