System Air Flow

SYSTEM AIR FLOW DESCRIPTION
The illustration contain system vacuum schematics and vacuum motor charts which show vacuum routings and air flow when the controls are set at their various positions.

OFF
When the function selector knob is in the OFF position:
- the heater and A/C air inlet duct door is at full vacuum. As a result, outside air is blocked and recirculated air is admitted to the system.
- the heater air damper door is at no vacuum, and the windshield defroster door is at full vacuum, blocking off the passages to the windshield defroster nozzle.
- the blower motor and A/C compressor are OFF

MAX A/C
When the function selector knob is in the MAX A/C position:
- the heater and A/C air inlet duct door is at full vacuum, closing off outside air and admitting only recirculated air.
- the heater air damper door is at full vacuum, blocking air flow to the heater outlet floor duct.
- the windshield defroster door is at full vacuum, blocking air flow to the windshield defroster nozzle.
- temperature control is usually set for maximum cold but may be heated if desired.
- air will be picked up at the recirculation opening by the blower motor. Air flow 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.
- A/C compressor will operate.
- blower motor is ON.

A/C
When the function selector knob is in the A/C position:
- the heater and A/C air inlet duct door is set at no vacuum, blocking the recirculation passage and admitting outside air through the pollen filter.
- all other door positions are the same as those previously described for the MAX A/C setting.
- temperature setting can be changed manually.
- the A/C compressor will operate.
- blower motor is ON.

PANEL
When the function selector knob is in the PANEL position:
- the heater and A/C 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.
- the heater air damper door is at full vacuum to block air flow to the heater outlet floor ducts.
- the windshield defroster door is at full vacuum, blocking airflow to the windshield defroster nozzle.
- the temperature setting can be changed manually as desired.
- blower motor is ON.

PNL/FLR
When the function selector knob is in the PNL/FLR position:
- the heater and A/C air inlet duct door is in the no vacuum position, blocking recirculating air and admitting outside air.
- the heater air damper door is in the partial vacuum position, allowing air flow to both the heater outlet floor duct and A/C register.
- the windshield defroster door is at full vacuum, blocking air flow to the windshield defroster nozzle.
- the temperature setting can be changed manually as desired.
- blower motor is ON.

FLOOR
When the function selector knob is in the FLOOR position:
- the heater and A/C air inlet duct door is in the no vacuum position, blocking recirculating air and admitting outside air.
- the heater air damper door is in the no vacuum position, closing off airflow to the A/C registers.
- the A/C air temperature control door can be positioned to mix air flowing through the heater core and air from outside to achieve the desired temperature level.
- the windshield defroster door is in the full vacuum position, blocking air circulation to the panel windshield defroster nozzle.
- blower motor is ON.

FLR-DEF
When the function selector knob is in the FLR/DEF position:
- the heater and A/C air inlet duct door and the heater air damper door are in the no vacuum position.
- the windshield defroster door is in the partial vacuum position, allowing air flow to both heater outlet floor ducts and windshield defroster nozzle.
- the A/C compressor operates to dehumidify the air and reduce windshield fogging.
- blower motor is ON.

DEFROST
When the function selector knob is in the DEFROST position:
- the heater and A/C air inlet duct door is in the no vacuum position, admitting outside air.
- both the heater air damper door and the windshield defroster door are in the no vacuum position so that most of the incoming air is directed to the windshield defroster nozzle. There is also air flow to the window defogger nozzles.
- the temperature control knob setting will determine the amount of heat introduced into the airflow.
- A/C compressor operates to dehumidify the air and reduce windshield fogging.
- blower motor is on.