System Air Flow

MAX A/C












When MAX A/C is selected:
- The air inlet duct door is at full vacuum, closing off outside air and admitting only recirculated air
- The heater water control valve is at full vacuum, preventing hot coolant from reaching the heater core.
- The panel/defrost door is at full vacuum and the floor/panel door is at no vacuum, directing airflow to the A/C registers.
- Temperature control is usually set for maximum cold but because the heater water control valve is preventing hot coolant from reaching the heater core, the air cannot be heated in any temperature control position.
- Air will be picked up at the recirc opening by the blower motor. With the temperature control set for maximum cold, airflow across the A/C evaporator core will be diverted past the heater core and then directed into the passenger compartment through the instrument panel A/C registers. There is also some airflow to the side window demisters.
- The A/C compressor will be enabled when MAX A/C is selected.
- The blower motor is on.

When A/C is selected:
- The air inlet duct door is set at no vacuum, blocking the recirc passage and admitting outside air.
- The heater water control valve is also at no vacuum, allowing hot coolant into the heater core.
- All other door positions are the same as described under MAX A/C.
- Temperature setting can be changed manually.
- The A/C compressor will be enabled when A/C is selected.
- The blower motor is on.

VENT







When VENT is selected:
- The air inlet duct door, with no vacuum being applied, will block recirculated air and admit outside air. From there, air flows through the system to the instrument panel A/C registers. There is also some airflow to the side window demisters.
- The floor/panel door is in the no vacuum position to block airflow to the heater outlet floor duct.
- The panel/defrost door is at full vacuum, closing off airflow to the windshield defroster hose nozzle.
- The temperature can be adjusted manually to heat the air but the air cannot be cooled below the outside temperature.
- The A/C compressor will be disabled when VENT is selected.
- The blower motor is on.


OFF







When OFF is selected:
- The A/C inlet duct door is at full vacuum, closing off outside air and admitting only recirc air.
- The heater water control valve is at full vacuum, preventing hot coolant from reaching the heater core.
- The floor/panel and panel/defrost doors are at full vacuum, closing off the passages to the A/C registers.
- The blower motor and the A/C compressor are off.

PANEL/FLOOR







When PANEL/FLOOR is selected:
- The air inlet duct door is set at no vacuum, blocking the recirc passage and admitting outside air.
- The heater water control valve is also at no vacuum, allowing hot coolant into the heater core.
- The floor/panel air flow door is in the partial vacuum position, allowing airflow to both the A/C registers and the heater outlet floor duct.
- The panel/defrost air flow door is at full vacuum, closing off airflow to the windshield defroster hose nozzle and directing airflow to the A/C registers. There is also some airflow to the side window demisters.
- The A/C compressor will be enabled when PANEL/FLOOR is selected.
- The blower motor is on.

FLOOR







When the FLOOR is selected:
- The air inlet duct door is in the no vacuum position, blocking recirc air and admitting outside air.
- The heater water control valve is also at no vacuum, allowing hot coolant into the heater core.
- The floor/panel air flow door is in the full vacuum position, directing all airflow to the heater outlet floor duct. There is also some airflow to the side window demisters.
- The temperature can be adjusted to mix air flowing through and around the heater core to achieve the desired temperature level.
- The panel/defrost air flow door is in the no vacuum position, blocking air circulation to the panel A/C registers.
- The A/C compressor will be disabled when FLOOR is selected.
- The blower motor is on.

FLOOR/DEFROST







When the FLOOR/DEFROST is selected:
- The air inlet duct door is in the no vacuum position blocking recirc air and admitting outside air.
- The heater water control valve is also at no vacuum, allowing hot coolant into the heater core.
- The floor/panel air flow door is in the partial vacuum position, allowing airflow to both the windshield defroster hose nozzle and the heater outlet floor duct.
- The panel/defrost air flow door is in the no vacuum position, directing airflow to the windshield defroster hose nozzle. There is also some airflow to the side window demisters.
- The A/C compressor will be enabled when FLOOR/DEFROST is selected to dehumidify the air and reduce windshield fogging.
- The blower motor is on.

DEFROST







When the DEFROST is selected:
- The air inlet duct door is in the no vacuum position, admitting outside air.
- The heater water control valve is also at no vacuum, allowing hot coolant into the heater core.
- Both the floor/panel air flow door and the panel/defrost air flow door are in the no vacuum position so that most of the incoming air is directed to the windshield defroster hose nozzle. There is also airflow to the side window demisters.
- The temperature setting will determine the amount of air that is directed through the heater core and the amount that bypasses the heater core.
- The A/C compressor will be enabled when DEFROST is selected to dehumidify the air and reduce windshield fogging.
- The blower motor is on.