GMC 2002 Sierra - Manual (Page 215)

3-12
Your vehicle has air
outlets in the center and
on the sides of your
instrument panel.
You can move the levers from side - to - side or up and
down to direct the flow of air. The left driver and
passenger outlets on vehicles equipped with air
conditioning have shut off levers. Turn the knob
counterclockwise to shut off air flow or clockwise to
allow air flow. When you close an outlet, it will increase
the flow of air coming out of any outlets that are open.
The center outlet does not completely shut off airflow.
Ventilation Tips
D Keep the hood and front air inlet free of ice, snow or
any other obstruction (such as leaves). The heater
and defroster will work far better, reducing the
chance of fogging the inside of your windows.
D When you enter a vehicle in cold weather, turn the
fan knob all the way to the right for a few moments
before driving. This helps clear the intake ducts of
snow and moisture, and reduces the chance of
fogging the inside of your windows.
D Keep the air path under the front seats clear of
objects. This helps air to circulate throughout
your vehicle.
D The use of hood air deflectors may adversely
affect the performance of the heating and air
conditioning system.