GMC SIERRA 2002, Manual

Page: 213 / 499

3-10
Heating
The heater works best if you keep your windows closed
while using it. On cold days, use the floor or bi
-
level
setting with the temperature knob in the red area.
On cold days, approximately 32
_F (
-
0
_C) or lower, if
your vehicle is equipped with an automatic transmission,
you may experience differences in how the transmission
shifts until the engine is warm. This feature
automatically reduces the time it takes for the engine to
reach normal operating temperature and shortens the
time it takes the heater to reach full output.
If you use the engine coolant heater before starting your
engine in cold weather, 20
_F (
-
8
_C) or lower, the
heating system will produce warmer air faster to heat the
passenger compartment.
The use of an engine coolant heater also reduces the
time it takes for the engine to reach normal operating
temperature. For more information, see “Engine Coolant
Heater” in the Index.
Defogging and Defrosting
On cool, humid days, use defrost to keep the windshield
and side windows clear. Use defrost to remove fog or ice
from the windshield in extremely humid or cold
conditions. Use defrost with the temperature knob
toward the red area and the fan control turned all the
way to the right.
Rear Window Defogger (If Equipped)
If you see lines running across the rear window, your
vehicle has a rear window defogger. The lines warm
the glass.
To turn on the rear window
defogger, press this button
next to the fan knob.
The rear window
defogger will only work
if the ignition is in RUN.
For best results, clear the
window of as much snow
or ice as possible.