GMC 2003 C4C042 Owner's Manual page 172

Heater/Air Conditioning Controls
(If Equipped)
If your vehicle has air conditioning, the heater/air
conditioning control panel will look like this.
Fan Knob
The knob on the left side of the control panel regulates
the fan speed. It has four speeds.
To increase airflow, turn the knob clockwise. To
decrease airflow, turn it counterclockwise. To turn the
fan off, turn the mode knob on the far right all the way
counterclockwise.
Temperature Knob
The middle knob on the control panel is used to adjust
the temperature of the air flowing into the passenger
compartment of your vehicle.
Turn the knob toward the red area for warmer air.
Turn the knob toward the blue area for cooler air.
Mode Knob
The knob on the right side of the control panel is used to
select the direction of the air flowing into the vehicle.
(Maximum Air Conditioning): Turn the right
knob to maximum air conditioning for maximum
cooling. This setting puts the system in the recirculation
mode and helps to maximize your air conditioner's
performance and your vehicle's fuel economy. This
setting also cools the air the fastest. After the vehicle's
interior reaches a comfortable temperature, turn the
knob clockwise to place the air conditioning system in
the regular air conditioning mode.
(Air Conditioning): This setting is used for
normal cooling on hot days. It cools outside air and
directs it through the instrument panel vents.
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