Ford Ranger Owner's Manual page 72

Controls and Features
Climate control knobs (heater only)
To turn your heater system on, select any position except OFF.
This turns the fan on and allows airflow into the vehicle. To
turn your heater off, select OFF.
Temperature selection
The temperature control knob is the rotating knob located at the
center of the control with tapered red and blue bands
surrounding most of the knob. The wide red part of the band
(full right) is the heat or warmer area. The wide blue area (full
left) is the cool or unheated temperature area. Any position
selected between full right and full left will give a temperature
between the two extreme temperatures. The cool temperature
you select will not be cooler than the outside temperature.
H Fan speed adjustment
The H (left) knob on the control is the fan control knob which
controls the volume of airflow. Rotate the H knob to the right
to increase fan speed and increase the amount of air entering
the vehicle. Four fan speed positons are available and are
indicated by dots beside the H control knob. The largest dot is
high speed position.
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