GMC 2002 Envoy - Manual (Page 182)

3-8
If your vehicle has the automatic system, in AUTO
mode the system will cool and dehumidify the air
inside the vehicle. Also while in AUTO mode, the
system will maximize its performance by using
recirculation as necessary.
On cool, but sunny days, with the manual system or
through manual operation of the automatic system,
use bi
- level to deliver warm air to the floor and cooler
air to the instrument panel outlets. To warm or cool
the air delivered, turn the temperature control to the
desired setting.
Heating
If you have the manual system, on cold days use floor
with the temperature lever in the red area. If you have
the automatic system, press AUTO and adjust the
temperature by turning the temperature knob clockwise
or counterclockwise. You may also adjust the automatic
system manually by pressing the MODE button and
selecting floor. Again, adjust the temperature by turning
the temperature knob clockwise or counterclockwise.
With either system, outside air will be heated and sent
through the floor outlets. The heater works best if you
keep the windows closed while using it.
Defogging and Defrosting
On cool, humid days, use defog to keep the windshield
and side windows clear. Use front defrost to remove fog
or ice from the windshield quickly in extremely humid
or cold conditions.
If your vehicle has the manual system, select defog and
adjust the fan speed to your comfort level. Turn the air
conditioning on to help dehumidify the air. Use front
defrost with the temperature toward the red area and the
fan control toward high.
If your vehicle has the automatic system and you select
FRONT defrost or defog from AUTO, the system will
control the fan speed. Adjust the temperature and fan
speed to your comfort level. After the windshield is
clear, adjust the temperature to your normal setting and
select the AUTO button and return to AUTO mode and
fan control.
For maximum front defrost performance under extreme
icing or frosting conditions, increase the temperature
setting to 90
_F (32_C) and increase the fan speed
to high.