ad blue GMC SONOMA 1999 Owner's Manual

3-2
Comfort Controls
With these systems, you can control the heating, cooling
and ventilation in your vehicle.
Standard Climate Control System
Fan Control
The knob on the left side of the heating system control panel
controls the fan speed. To increase airflow, turn the knob
clockwise. To decrease airflow, turn it counterclockwise.
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. Turn the knob clockwise
toward the red area for warmer air. Turn the knob
counterclockwise toward the blue area for cooler air.Mode Knob
The right knob on the control panel allows you to
choose the direction of air delivery.
OFF: This setting turns the system off. Some outside
air will still enter the vehicle whenever the vehicle is
moving forward.
VENT: This setting directs most of the air through
the instrument panel outlets and a small amount through
the floor outlets.
BI-LEVEL: Air is delivered through the heater
floor outlets as well as the instrument panel outlets.
HEATER: This setting directs most of the
warmed air through the heater floor outlets and some
air through the windshield defroster outlets.
BLEND: Airflow is divided equally between the
heater floor outlet and the windshield defroster outlets.
DEFROST: This setting directs most air through
the windshield defroster outlets and some through the
heater outlets.

3-3 Optional Climate Control System
Fan Control
The knob on the left side of the heating system
control panel controls the fan speed. To increase airflow,
turn the knob clockwise. To decrease airflow, turn
it counterclockwise.
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. Turn the knob clockwise
toward the red area for warmer air. Turn the knob
counterclockwise toward the blue area for cooler air.Mode Knob
The right knob on the control panel allows you to
choose the direction of air delivery.
OFF: This setting turns the system off. Some outside
air will still enter the vehicle whenever the vehicle is
moving forward.
MAX A/C: This setting provides maximum cooling
with the least amount of work. MAX A/C recirculates
much of the air inside your vehicle so it cools quickly.
This setting directs most of the air through the
instrument panel vents and a small amount through
the floor vents.
A/C: This setting cools the air entering your vehicle and
directs most of the air through the instrument panel
vents and a small amount through the floor vents.
BI-LEVEL A/C: This setting cools the air
entering your vehicle and directs it through the heater
floor outlets as well as the instrument panel outlets.
VENT: This setting directs most of the air through
the instrument panel outlets and a small amount through
the floor outlets. The air conditioning compressor is not
working when VENT is selected.