Ford 2003 Mustang Workshop Manual page 3046

control motor is at no vacuum, closing off airflow to the defrost duct, side window demisters,
floor duct and instrument panel A/C registers.
The A/C compressor will not operate.
The blower motor is off.
FLOOR
When FLOOR is selected:
The air inlet door vacuum control motor is at no vacuum, admitting only outside air into the
passenger compartment.
The panel/floor door vacuum control motor is at full vacuum and the panel/defrost door vacuum
control motor is at no vacuum, directing airflow to the floor duct. A small amount of airflow from
the side window demisters will be present.
The temperature can be adjusted to heat the air, but the air cannot be cooled below the outside
temperature.
The A/C compressor will not operate.
The blower motor is on.
FLOOR/DEFROST
When FLOOR/DEFROST is selected:
The air inlet door vacuum control motor is at no vacuum, admitting only outside air into the
passenger compartment.
The panel/floor door vacuum control motor is at partial vacuum and the panel/defrost door
vacuum control motor is at no vacuum, directing airflow to the floor duct, the defroster duct, and
the side window demisters.
The temperature can be adjusted to heat or cool the air below the outside temperature.