2001 GMC SIERRA AC system

2-102
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. See ªEngine
Overheatingº in the Index for further information.
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
(V8 Gasoline Engines Only)
This message is displayed
when the cooling system
temperature gets too hot and
the engine further enters
the engine coolant
protection mode.
If your vehicle is equipped with the 8.1L engine, this
light may come on because of an electronic throttle
control system fault. See ªEngine Overheatingº in
the Index for further information.

2-103
Check Eng Oil Pressure
This message is displayed
when the engine oil pressure
is low.
See ªOil Pressure Gageº in the Index for more information.
Check Eng Oil Level (Gasoline Engine)
This message is displayed
when the engine oil level
is low.
Once oil is added, it may need time to drain and settle in
the engine before this message will turn off. It is best to
let the engine cool down (if it is hot) or warm up (if it is
cold) and cycle the ignition to be sure this message turns
off. Refer to the dipstick for the correct level.
See ªEngine Oilº in the Index on how to check the oil
level and for what type of oil to add.
Change Engine Oil
This message is displayed
when the engine oil needs to
be changed. The message
is only displayed for
15 seconds at the start of
each ignition cycle.
When you change the engine oil, be sure to reset the
Engine Oil Life Monitor. See ªEngine Oil, When to
Changeº in the Index.
Security
This message is
displayed when the content
theft
-deterrent system has
been activated and
also monitors the
Passlock

System.
If the security message is displayed continuously while
driving and stays on, there may be a problem with the
Passlock System. Your vehicle will not be protected by
Passlock, and you should see your GM dealer.

2-104
Service 4WD (If Equipped)
If the SERVICE 4WD
message comes on, there
may be a problem with the
automatic transfer case and
service is required.
Malfunctions can be indicated by the system before any
problem is apparent, which may prevent serious damage to
the vehicle. This system is also designed to assist your
service technician in correctly diagnosing a malfunction.
Low Washer Fluid
This message is displayed
when the vehicle is low on
windshield washer fluid.
The message is only
displayed for 15 seconds
at the start of each
ignition cycle.
For more information see, ªWindshield Washer Fluidº in
the Index.
Cargo Lamp On
This message is displayed
when the cargo lamp is
turned on and the ignition
key is turned to RUN.
Low Fuel
This message is displayed
when your vehicle is low
on fuel.
Refer to the fuel gage for a better indication of the
amount of fuel remaining in the fuel tank.

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
-2 Standard Comfort Controls
3
-3 Heater and Air Conditioning Comfort
Controls (If Equipped)
3
-5 Electronic Climate Control System
(If Equipped)
3
-12 Air Conditioning
3
-13 Heating
3
-13 Defogging and Defrosting
3
-13 Rear Window Defogger (If Equipped)
3
-14 Ventilation System
3
-16 Audio Systems
3
-16 Setting the Clock for Systems with
SET Button
3
-16 Setting the Clock for Systems with HR and
MN Buttons3
-16 AM-FM Stereo
3
-18 AM-FM Stereo with Cassette Tape Player
(If Equipped)
3
-20 AM-FM Stereo with Cassette Tape Player and
Automatic Tone Control (If Equipped)
3
-25 AM-FM Stereo with Compact Disc Player and
Automatic Tone Control (If Equipped)
3
-29 Remote Cassette Tape Player (If Equipped)
3
-30 Theft-Deterrent Feature (If Equipped)
3
-32 Understanding Radio Reception
3
-33 Tips About Your Audio System
3
-34 Care of Your Cassette Tape Player
3
-35 Care of Your Compact Discs
3
-35 Care of Your Compact Disc Player
3
-35 Fixed Mast Antenna

3-4
BLEND: Airflow is delivered through the heater
floor outlets, center floor console outlets (if equipped),
the windshield defroster outlets and the side window
defroster outlets. The air flow can be divided between
HEATER and DEFROST depending upon where
the knob is placed between the settings. The air
conditioning compressor may run to dehumidify the
air to prevent window fogging.
DEFROST: This setting directs most of the air
through the windshield defroster outlets, side window
defroster outlets and some air through the heater outlets
and center floor console outlets (if equipped). If air from
the center floor console outlets is not desired or more
defroster performance is desired, turn the vents off at
the console. When in the DEFROST mode, the air
conditioning compressor may run to dehumidify the
air to prevent window fogging.
OUTSIDE AIR: Press this button to direct
the system to use outside air.
Pressing the OUTSIDE AIR button will cancel the
RECIRCULATION button.
RECIRCULATION: Press this button to
limit the amount of outside air entering your vehicle.
This is helpful when you are trying to limit odors
entering your vehicle or attempting to quickly cool
down the interior. Pressing RECIRCULATION will
recirculate air continuously.
RECIRCULATION is used when the fan control is OFF
to limit odors, outside air and dust from entering your
vehicle. All button lights will go off. The last setting
selected will activate when the blower is turned back on.
Pressing the RECIRCULATION button will cancel
the OUTSIDE AIR button. To return to normal
operation and to prevent stale air, be sure to return
the OUTSIDE AIR.
Between HEATER and BLEND mode, outside air is forced
to reduce window fogging. If the RECIRCULATION
button is pressed, the LED indicator will flash three
times indicating that forced outside air is activated and
RECIRCULATION is not available.

3-5
The auto recirculation feature will activate when the
following are true:

the air conditioning system is activated,

the OUTSIDE AIR button is on, and

the vehicle load is high due to city traffic,
extended idling or hot weather.
The system will automatically switch to the recirculation
mode to lower the system load and improve interior
comfort. The OUTSIDE AIR and RECIRCULATION
button LEDs will not change. The system will return
to the OUTSIDE AIR function when the system load
is reduced.
A/C: Press this button to turn the air conditioning
on and off. The system will cool and dehumidify the air
inside the vehicle when the A/C light is on.
Air conditioning will be automatically disabled when
the outside temperature drops below a level at which
air conditioning is ineffective.
Electronic Climate Control System
(If Equipped)
Fan Control
The knob on the left side of the electronic climate control
panel operates the fan speed. To manually increase
airflow, move the knob clockwise. To manually decrease
airflow, move it counterclockwise.
OFF: If the knob is in OFF, outside air will still enter
the vehicle, and will be directed based on the position of
the mode knob.

3-6
AUTO: If the knob is in AUTO, the fan speed will vary
as the system maintains the selected temperature.
When both the fan control and mode knobs are in the
AUTO position, the system will then automatically
maintain the desired cabin temperature as selected by
the temperature knob. Manual control of functions is
also available.
Temperature Knob
The middle knob on the control panel lets you select
the desired air temperature in your vehicle. This knob
will allow you to adjust the interior air temperature
independent of the function knob setting. Move the
knob clockwise toward 82 for warmer air. Move the knob
counterclockwise toward 66 for cooler air. When the
system is set for automatic operation, sensors will control
the fan/blower speed.
Full Hot: If you turn the temperature knob past 82
F
(28
C), the system will go into the ªfull hotº mode.
The system will remain at that maximum heating setting
and the fan will blow at the speed the fan knob is set to.
If the fan is in AUTO, it will run at full speed.
Full Cold: If you turn the temperature knob past 66
F
(19
C), the system will go into the ªfull coldº mode.
The system will remain at that maximum cooling setting
and the fan will blow at the speed the fan knob is set to.
If the fan is in AUTO, it will run at full speed.
Mode Knob
-- Automatic Operation
The right knob on the control panel allows you to
choose the direction of air delivery. When the system is
set for automatic operation, sensors will control the air
delivery mode. Air will come primarily from the floor or
instrument panel outlets, with some air directed to the
windshield to prevent fogging.
When the system is in AUTO mode, the air conditioning
light will turn on, and the recirculation and outside
air lights turn off. With the system in full auto control
(both the fan and mode knobs in AUTO), you still
have the ability to override any function. However,
continually overriding the outside air or the A/C
compressor will limit the ability of the system to
cool the vehicle quickly.
If you push a button for a function which is not
available, the light next to that button will flash
three times to alert you that it's not available.
To find your comfort zone, start with the 74
F (23
C)
setting and allow about 20 minutes for the system to
adjust the temperature if necessary.

3-7
With the automatic setting, the air conditioning
compressor automatically cycles when needed to cool the
air. In cold weather, when the system senses the need for
heat, the airflow will be directed out of the floor outlets.
As the interior temperature approaches a desired setting,
the blower speed will decrease. To maintain interior
comfort, the airflow will adjust between the instrument
panel air outlets and floor outlets. On bright sunny days
in cool weather, the airflow may come out of the air
conditioning and floor outlets (bi
-level mode) to
maintain comfort and prevent stuffiness.
To avoid blowing cold air in cold weather, the system
will delay turning on the fan until warm air is available.
The length of delay depends on the outside air
temperature, engine coolant temperature or the time since
the engine was last started. As the coolant warms up, the
fan speed will gradually increase and air will flow from
the heater outlets, with some airflow to the windshield
to prevent fogging under most normal conditions.
Be careful not to put anything over the solar sensor
located around the center of the instrument panel.
This sensor is used by the automatic system to
regulate temperature.Mode Knob
-- Manual Operation
The right knob on the control panel allows you to
choose the direction of air delivery.
You can choose to set the climate control system
yourself, or let the system work for you by placing the
system in AUTO mode. See ªMode Knob
-- Automatic
Operationº earlier in this section.
PANEL: 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.
The air conditioning compressor may run to dehumidify
the air to prevent window fogging.