Ford 2003 Mustang Owner's Manual page 26

Controls and features
Since the air conditioner removes considerable
moisture from the air during operation, it is normal
if clear water drips on the ground under the air
conditioner drain while the system is working and
even after you have stopped the vehicle.
Under normal conditions, your vehicle's climate
control system should be left in any position other
than MAX A/C or OFF when the vehicle is parked.
This allows the vehicle to "breathe" through the
outside air inlet duct. Prior to turning off the
ignition in snowy or dirty conditions, ensure that the
climate control system is turned off.
F -Distributes outside air through the
windshield defroster ducts. It can be used to clear
ice or fog from the windshield. If the outside air
temperature is about 10°C (50°F) or higher, the
air conditioner will automatically dehumidify the
air to reduce fogging.
-Distributes outside air through the
windshield defroster ducts and the floor ducts.
Heating and air conditioning capabilities are
provided in this mode. The air will be heated or
cooled based on the temperature selection. For
added customer comfort, the air distributed
through the floor ducts will be slightly warmer
than the air sent to the windshield defroster
ducts. If the temperature is about 10°C (50°F) or
higher, the air conditioner will automatically
dehumidify the air to reduce fogging.
-Allows for maximum heating by distributing
outside air through the floor ducts. However, the
air cannot be cooled below the outside
temperature because the air conditioning does not
operate in this mode.
-Distributes outside air through the
instrument panel registers. However, the air
cannot be cooled below the outside temperature
because the air conditioning does not operate in
this mode.
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