GMC 2003 C4C042, Owner'S Manual

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3-6
Rear Heater (If Equipped)
If your vehicle has a rear
heater, the thumbwheel
for this feature is located
on the headliner.
To increase and decrease the flow of heated air to the
rear floor vents, turn the thumbwheel to the desired
fan speed.
To increase the flow of heated air, turn the thumbwheel
up. To turn the fan off, turn the thumbwheel down.
Ventilation System
For mild outside temperatures when little heating or
cooling is needed, turn the mode knob to vent to direct
outside air through your vehicle. Air will flow through
the instrument panel vents.
Your vehicle’s flow
-
through ventilation system supplies
outside air to the inside of your vehicle when it is
moving. With the side windows closed, air will flow into
the front air inlet grilles at the base of the windshield,
through the vehicle and out the rear air exhaust valve.
Outside air will also enter the vehicle when the heater or
the air conditioning compressor is running.
Your vehicle has air vents
near the center and on the
sides of the instrument
panel that allow you to
adjust the direction and the
amount of airflow inside
the vehicle.
Move the thumbwheel on the vent up or down to direct
the airflow. Increase or reduce the amount of airflow by
opening and closing the louvers. The vents can be
moved side
-
to
-
side to direct the airflow.
When you close a vent, it will increase the flow of air
coming out of any vents that are open.