2002 GMC SIERRA air conditioning

2-79 Low Coolant
This message is displayed
when the cooling system is
low on coolant.
The engine may overheat. See ªEngine Coolantº in the
Index and have your vehicle serviced as soon as you can.
Check Coolant Temp
This message is displayed
when the cooling system
temperature gets hot.
Check the coolant temperature gage and the coolant
level. See ªEngine Coolantº and ªEngine Coolant
Temperature Gageº in the Index.
Engine Overheated
This message is displayed
when the cooling system
temperature gets too hot.
This message will be displayed after the air conditioning
system has automatically turned off for the engine
coolant protection mode. See ªEngine Overheatingº
in the Index for further information.
Reduced Engine Power
This message is displayed
when the cooling system
temperature gets too hot
and the engine further
enters the engine coolant
protection mode.
See ªEngine Overheatingº in the Index for
further information.

3-
3-1
Section 3 Comfort Controls and Audio Systems
In this section, you'll find out how to operate the comfort control and audio systems offered with your vehicle.
Be sure to read about the particular systems supplied with your vehicle.
3
-2 Comfort Controls
3
-4 Air Conditioning
3
-5 Heating
3
-5 Defogging and Defrosting
3
-6 Rear Window Defogger
3
-7 Ventilation System
3
-8 Audio Systems
3
-8 Setting the Clock for Systems with HR and
MIN Buttons
3
-9AM-FM Stereo with Cassette Tape Player and
Automatic Tone Control3
-13 Rear Seat Audio (RSA)
3
-16 Compact Disc Changer
3
-19 Theft-Deterrent Feature
3
-21 Audio Steering Wheel Controls
3
-22 Understanding Radio Reception
3
-22 Tips About Your Audio System
3
-23 Care of Your Cassette Tape Player
3
-24 Care of Your Compact Discs
3
-24 Care of Your Compact Disc Player
3
-24 Fixed Mast Antenna

3-2
Comfort Controls
Heater and Air Conditioning Comfort
Controls
Fan Knob
The knob on the left side of the control panel adjusts the
fan speed. To increase airflow, turn the knob clockwise.
To decrease airflow, turn it counterclockwise. To turn
the fan off, turn the knob to OFF.Temperature Knob
The middle knob on the control panel lets you select the
temperature of the air flowing into the passenger area.
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.
(Vent): This mode directs the air through the
instrument panel outlets and the center floor console
outlets.
(Bi-Level): Air is delivered through the
instrument panel outlets and center floor console outlets,
as well as the floor outlets. The air flow can be divided
between panel and floor depending upon where the knob
is placed. Pressing the A/C button while in this mode
causes cooler air to come out of the instrument panel
outlets and center floor console outlets and warmer air
to come out of the floor outlets.

3-3
(Floor): This mode directs most of the air through
the floor outlets and center floor console outlets, as well
as some air through the windshield defroster outlets and
side window defroster outlets. If air from the center
floor console outlets is not desired, turn the vents off at
the console.
(Defog): Airflow is delivered through the floor
outlets, center floor console outlets, the windshield
defroster outlets and the side window defroster outlets.
The air flow can be divided between floor and defrost
depending upon where the knob is placed. When in
blend mode, the air conditioning compressor may run
to assist in dehumidifying the air and limit window
fogging.
(Defrost): This mode directs most of the air
through the windshield defroster outlets with airflow
also delivered from the side window and the floor
outlets. When in defrost mode, the air conditioning
compressor may run to assist in dehumidifying the air
and limit window fogging.Mode Buttons
(Outside Air): This mode should be used for
normal system operation and directs the system to use
outside air. Using outside air will limit stale air odors
and help to prevent excessively humid interior air
(from wet boots or clothing or maximum passenger
loads) from being redirected onto windows.
Pressing the outside air button will cancel the
recirculation button.
(Recirculation): This mode limits the amount of
outside air entering the vehicle to a very small amount.
This will be helpful to limit odors entering the vehicle
and will assist in reaching comfort in very hot
temperature conditions. Pressing recirculation will cause
the system to recirculate interior air continuously and
may cause the vehicle windows to fog if the passenger
compartment floor is excessively wet.
Pressing the recirculation button will cancel outside air
operation. To return to normal system operation and to
prevent stale passenger compartment air, be sure to
return to the outside air position.

3-4
Recirculation will not be available in floor, blend, or
defrost modes. This helps reduce window fogging.
If the recirculation button is pressed in these modes,
the LED indicator for recirculation will flash three times
indicating that outside air is activated and recirculation
is not available.
If the air conditioning system is activated and system
demand is high in situations such as city traffic, idling,
or very hot weather, the system will automatically
switch from outside air to recirculation. The LED
indicator will not change. After demand on the system
is reduced, the system will return to outside air.
A/C (Air Conditioning): This button is used to
control the air conditioning compressor. Turning the
system on will allow air to be cooled and dehumidified
inside the vehicle.
Air conditioning will be automatically disabled when
the outside air temperature drops below a level at which
air conditioning is effective.
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 its best.
The A/C button, located below the mode knob, allows
the air coming into your vehicle to be cooled. This
setting is useful for normal cooling on hot days. When
you use air conditioning with the recirculation button
pressed, turn off recirculation as soon as the vehicle
reaches a comfortable interior temperature.
Using air conditioning with the recirculation mode
active 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 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 and use outside air after the vehicle
reaches a comfortable interior temperature. When the
right knob on the control panel is between floor and
defrost, recirculation will not function to reduce window
fogging.

3-7 Ventilation System
For mild outside temperatures when little heating or
cooling is needed, use vent and the outside air setting to
direct outside air through your vehicle. Air will flow in
through the instrument panel outlets.
Your vehicle's ventilation system supplies outside air to
the inside of your vehicle when it is moving. With the
side windows closed, air will flow into the front air
inlet grilles, through the vehicle, and out the air
exhaust valves.
Outside air will also enter the vehicle when the heater or
the air conditioning compressor is running, unless you
have the recirculation button pressed. For more
information on the recirculation button, see ªAir
Conditioningº earlier in this section.
Your vehicle has air
outlets in the center and
on the sides of your
instrument panel.
You can move the outlets from side
-to-side or up and
down to direct the flow of air. The left driver and
passenger outlets have shut off levers. Turn the lever to
the left to shut off air flow or to the right to allow air
flow. When you close an outlet, it will increase the flow
of air coming out of any outlets that are open. The
center outlet does not completely shut off airflow.

3-8
Ventilation Tips

Keep the hood and front air inlet free of ice, snow or
any other obstruction (such as leaves). The heater
and defroster will work far better, reducing the
chance of fogging the inside of your windows.

When you enter a vehicle in cold weather, turn the
fan knob all the way toward the red area for a few
moments before driving. This helps clear the intake
ducts of snow and moisture, and reduces the chance
of fogging the inside of your windows.

Keep the air path under the front seats clear of
objects. This helps air to circulate throughout
your vehicle.

The use of non
-GM approved hood air deflectors
may adversely affect the performance of the heating
and air conditioning system.
Passenger Compartment Air Filter
Your vehicle is equipped with a passenger compartment
air filter, which filters outside air entering the vehicle.
For information on replacing the filter see ªPassenger
Compartment Air Filterº in the Index.
Audio Systems
Your audio system has been designed to operate easily
and give years of listening pleasure. You will get the
most enjoyment out of it if you acquaint yourself with it
first. Find out what your audio system can do and how
to operate all of its controls to be sure you're getting the
most out of the advanced engineering that went into it.
Your vehicle has a feature called Retained Accessory
Power (RAP). With RAP, you can play your audio
system even after the ignition is turned off. See
ªRetained Accessory Powerº in the Index.
Setting the Clock for Systems with HR and
MN Buttons
Press and hold HR until the correct hour appears on the
display. Press and hold MN until the correct minute
appears on the display. To display the clock with the
ignition off, press RECALL or HR/MN and the time
will be displayed for a few seconds. There is an initial
two
-second delay before the clock goes into the
time
-set mode.

6-74
Fuse Usage
B/U LP Backup Lamps, Automatic
Transmission Shift Lock
Control System
ATC Automatic Transfer Case
RR DEFOG Rear Window Defogger, Heated
Mirrors (Relay)
RTD Not Used
RR PRK Passenger's Side Parking Lamps
ECM B VCM/PCM
F/PMP Fuel Pump (Relay)
O2 A Oxygen Sensors
O2 B Oxygen Sensors
LR PRK Driver's Side Parking Lamps
RR DEFOG Rear Window Defogger,
Heated Mirrors
HDLP Headlamps (Relay)
TRL PRK Parking Lamps Trailer WiringFuse Usage
PRIME Not Used
RT HDLP Passenger's Side Headlamps
DRL Daytime Running Lamps (Relay)
HTD MIR Heated Mirrors
LT HDLP Driver's Side Headlamps
A/C Air Conditioning
AUX PWR Cigarette Lighter, Auxiliary
Power Outlets
SEO 2 Special Equipment Option Power,
Power Seats, Aux Roof Mnt Lamp
SEO 1 Special Equipment Option Power,
Aux Roof Mnt Lamp
DRL Daytime Running Lamps
A/C A/C (Relay)
FOG LP Fog Lamps
FOG LP Fog Lamps (Relay)
RADIO Audio System, Instrument Panel
Cluster, Climate Control System