Control System Logic: Defrost

WARNING: This page is about a different car, the 2013 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.

When DEFROST is selected:

the RECIRC request button is disabled. The air inlet door opens, allowing only outside air into the passenger compartment.
the mode doors direct airflow to the defroster duct and side window demisters. A small amount of airflow from the floor duct is present.
blended air temperature is available.
the A/C request button toggles the indicator on and off. To reduce fogging, the A/C compressor operates automatically, regardless of indicator status, if the outside temperature is above approximately 6°C (42.8°F).
the blower motor is on.