Vacuum Schematic

Fig 1: Vacuum Schematic

Courtesy of MAZDA MOTORS CORP.

When DEFROST is selected:

• The air inlet blend door is in the no vacuum position, allowing outside air.
• The defrost blend door is at no vacuum, directing the airflow to the windshield through the defroster ducts and the side windows through the demister ducts.
• The panel airflow door and the footwell airflow 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 demister and hose.
• The temperature control knob 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 is enabled when DEFROST is selected to dehumidify the air and reduce windshield fogging.
• The blower motor is on.