Ford Windstar Owner's Manual page 93

Rear fan control knob
The rear passenger compartment climate control panel has a Fan
Speed Knob which controls the speed (Low, Medium Low,
Medium High, or High) at which air is discharged from the
registers whenever the Rear Control Knob on the front panel
climate control panel is in REAR CTRL.
Front passengers determine the temperature and location of the
airflow for rear passengers by setting the Function Selector
Knob in the front climate control panel in either a heat or A/C
mode.
If an A/C mode is chosen, rear passengers will receive FULL
COOL (air-conditioned) air out of the side and upper rear
registers. If a heat mode or the Q (PANEL) mode is chosen,
rear passengers will receive FULL WARM (heated) air out of
the lower rear registers.
Rear passengers do not have the ability to adjust the
temperature or select the location of the airflow from the
auxiliary climate control system. Rear passengers can adjust the
Rear Fan Speed Control Knob and air discharge (adjust
registers) for comfort.
NOTE: For maximum heating and cooling for front seat
passengers, set the rear fan switch to the m (OFF)
position.
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