GMC 1996 Sierra Owner's Manual page 133

Temperature Knob
The middle knob on the control panel lets you select the
relative temperature of the air flowing into the passenger
area of your vehicle. This knob will allow you to adjust
the relative air temperature independently of the
function knob setting. Move the knob clockwise
toward the red area for warmer air. Move the knob
counterclockwise toward the blue area for cooler air.
The right knob on the control panel allows you
to
choose the direction of air delivery. The control knob
can be placed in any position between two mode settings
to
blend the flow of air.
/J
VENT: This setting directs air through the
instrument panel outlets.
+H
VENT/HEAT Use this setting to divide airflow
between the floor outlets and instrument panel outlets.
+'
HEATER: This setting directs air through the
heater floor outlets.
+ e
+.
0
Q e
+'
DEFOG:
This setting directs air
to
the heater
outlets and toward the windshield.
DEFROST
This setting directs air toward the
windshield.
Air Conditioning
On hot days, open the windows long enough to let hot
air inside escape. This reduces the time it takes for your
vehicle to cool down. Then keep your windows closed
for the air conditioner to work it's best.
The recirculation button, between the fan and
temperature knobs, allows the air inside your vehicle to
be recirculated. This setting helps to maximize your air
conditioner's performance and your vehicle's fuel
economy. This setting also cools the air the fastest and
can be used to keep unwanted odors and/or dust from
entering the vehicle. When using the air conditioner,
turn off recirculation after the vehicle reaches a
comfortable interior temperature. When the right knob
on the control panel is between HEATER and
DEFROST, the recirculation feature will not function.