GMC SIERRA DENALI 2002, Manual

Page: 164 / 394

3-5
Heating
The heater works best if you keep your windows closed
while using it. On cold days, use the floor or bi
-
level
modes with the temperature knob in the red area.
On cold days, approximately 32
_F (
-
0
_C) or lower 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 blend mode to keep the
windshield and side windows clear. Use defrost mode to
remove fog or ice from the windshield in extremely
humid or cold conditions. Use defrost mode with the
temperature knob toward the red area and the fan knob
turned all the way clockwise.