2004 GMC SIERRA Owner's Manual

@(Recirculation):Press this button to limit the
amount of outside air entering your vehicle. The light on
the recirculation button will glow. This is helpful when you
are trying to limit odors entering your vehicle and for
maximum air conditioning performance in hot weather.
Press this button again to allow outside air to enter the
vehicle. The light on the recirculation button will go off.
Pressing this button also cancels the auto recirculation
feature. To resume the auto recirculation function, press
the AUTO button. Each time the vehicle is started, the
system will revert to the auto recirculation function.
If you select recirculation while in defrost, defog or ¯oor,
the light in the button will ¯ash and then go out to let you
know that this is not allowed. This is normal and helps to
prevent fogging.
When the weather is cool or damp, operating the system
in recirculation for extended periods of time may cause
fogging of the vehicle's windows. To clear the fog, select
either defog or front defrost.
You may also notice that the A/C compressor will run
while in recirculation mode. This is normal and helps to
prevent fogging.9(Off):Press this button to turn off the entire climate
control system. Outside air will still enter the vehicle, and
will be directed to the ¯oor. This direction can be changed
by pressing the mode button. The temperature can also
be adjusted using either temperature knob. Press the up
or down arrows on the fan switch, the defrost button, the
AUTO button, or the air conditioning button to turn the
system on when it is off.
Display
If you press the MODE button to select an air delivery
mode, the display will change to show you the selected
air delivery mode. After ten seconds, the display will
change to show the driver temperature setting and the
selected mode.
If you press the up or down arrows on the fan switch,
the display will change to show the selected fan speed.
After ten seconds, the display will change to show
the driver temperature setting and the selected mode.
3-29

Whenever you press AUTO, the display will change to
show the following:
·The current driver's set temperature and an arrow
for ®ve seconds
·The current passenger's set temperature setting
and an arrow for ®ve seconds
·The automatic air delivery mode and fan speed
If the driver's and passenger's temperature settings are
the same when AUTO is pressed, the temperature
setting and both arrows will be displayed for
®ve seconds along with the automatic air delivery
mode and fan speed. After the ®ve second update, the
display will change to show the temperature setting,
both arrows and AUTO.
Air Conditioning
#
(Air Conditioning):Press this button to turn the air
conditioning (A/C) compressor on and off. The
snow¯ake symbol will appear on the display when the
A/C is on.
Pressing this button when the outside temperature is
too cool for air conditioning will make the snow¯ake
symbol ¯ash three times and then turn off to let
you know the air conditioning mode is not available. If
the air conditioning is on and the outside temperature
drops below a temperature which is too cool for air
conditioning to be effective, the snow¯ake symbol will
turn off to let you know the air conditioning mode
has been canceled.
^(Air Conditioning Off):On some vehicles, when
you turn the air conditioning off, this symbol will appear
on the display. If your vehicle does not have this
symbol, the snow¯ake symbol will turn off to let you
know the air conditioning is off.
When air conditioning is selected or in AUTO mode, the
system will run the air conditioning automatically to cool
and dehumidify the air entering the vehicle. If you select
A/C off while in front defrost, defog or recirculation, the
A/C snow¯ake symbol will turn off, but the A/C
compressor will still run to help prevent fogging.
3-30

On hot days, open the windows long enough to let hot
inside air 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.
On cool, but sunny days while using manual operation
of the automatic system, use bi-level to deliver warm
air to the ¯oor and cooler air to the instrument
panel outlets. To warm or cool the air delivered, turn the
temperature knob to the desired setting.
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.
Heating
On cold days when using manual operation of the
automatic system, choose ¯oor mode to deliver air to
the ¯oor outlets. To warm or cool the air delivered, turn
the temperature knob to the desired setting.
If you want to use the automatic mode, press AUTO and
adjust the temperature by turning the temperature knob.
The heater works best if you keep the windows closed
while using it.
Defogging and Defrosting
You can use either defog or front defrost to clear fog or
frost from your windshield. Use the defog mode to
clear the windows of fog or moisture. Use the front
defrost button to defrost the front windshield.
-(Defog):Use this setting to clear the windows of fog
or moisture. Press the mode button to select this
setting. This setting will deliver air to the ¯oor and
windshield outlets.
0(Front Defrost):Press the front defrost button to
defrost the windshield. The system will automatically
control the fan speed if you select defrost from AUTO
mode. If the outside temperature is 40ÉF (4ÉC) or
warmer, your air conditioning compressor will
automatically run to help dehumidify the air and dry the
windshield.
3-31

Rear Window Defogger
If your vehicle has this feature, the lines you see on the
rear window warm the glass. The rear window
defogger uses a warming grid to remove fog from the
rear window.
<(Rear):Press this button to turn the rear window
defogger on or off. An indicator light in the button
will come on to let you know that the rear window
defogger is activated.
The rear window defogger will turn off about 10 minutes
after the button is pressed. If you need additional
warming time, press the button again.
If your vehicle is equipped with heated mirrors this
button will activate them.
Notice:Using a razor blade or sharp object to clear
the inside rear window may damage the rear
window defogger. Repairs would not be covered by
your warranty. Do not clear the inside of the rear
window with sharp objects.
Outlet Adjustment
Use the air outlets located
in the center and on the
side of your instrument
panel to direct the air¯ow.
Your vehicle has air outlets that allow you to adjust the
direction and amount of air¯ow inside the vehicle.
Move the louvers up or down. Use the thumbwheel next
to or underneath the outlet to close the louvers. For
the most efficient air¯ow and temperature control, keep
the outlet in the fully opened position.
Rear seat outlets can be used to adjust air¯ow toward
either seating area, the ¯oor or upward. Move the center
louvers up or down to direct the air¯ow.
3-32

Operation Tips
·
Keep the hood and front air inlets 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.
·Keep the air path under the front seats clear
of objects. This helps air to circulate throughout your
vehicle.
·Adding outside equipment to the front of your
vehicle, such as hood-air de¯ectors, etc., may affect
the performance of the heating and air conditioning
system. Check with your dealer before adding
equipment to the outside of your vehicle.
Warning Lights, Gages and
Indicators
Warning Lights, Gages, and
Indicators
This part describes the warning lights and gages that
may be on your vehicle. The pictures will help you
locate them.Warning lights and gages can signal that something is
wrong before it becomes serious enough to cause
an expensive repair or replacement. Paying attention to
your warning lights and gages could also save you
or others from injury.
Warning lights come on when there may be or is a
problem with one of your vehicle's functions. As you will
see in the details on the next few pages, some
warning lights come on brie¯y when you start the
engine just to let you know they're working. If you are
familiar with this section, you should not be alarmed
when this happens.
Gages can indicate when there may be or is a problem
with one of your vehicle's functions. Often gages
and warning lights work together to let you know when
there's a problem with your vehicle.
When one of the warning lights comes on and stays on
when you are driving, or when one of the gages shows
there may be a problem, check the section that tells you
what to do about it. Please follow this manual's advice.
Waiting to do repairs can be costly ± and even
dangerous. So please get to know your warning lights
and gages. They're a big help.
Your vehicle also has a driver information system that
works along with the warning lights and gages. See
Driver Information Center (DIC) on page 3-55.
3-33

Instrument Panel Cluster
Your instrument cluster is designed to let you know at a glance how your vehicle is running. You'll know how fast
you're going, about how much fuel you have and many other things you'll need to know to drive safely and
economically.
United States Heavy Duty Automatic Transmission version shown. Canada, Light Duty Automatic and Manual
Transmission Clusters similar.
3-34

Speedometer and Odometer
Your speedometer lets you see your speed in both
miles per hour (mph) and kilometers per hour (km/h).
Your odometer shows how far your vehicle has
been driven, in either miles (used in the United States)
or kilometers (used in Canada).
Trip Odometer
The trip odometer can tell you how far your vehicle has
been driven since you last set the trip odometer to zero.
Press the reset button to toggle between the trip
odometer and the regular odometer. Holding the reset
button for two seconds while the trip odometer is
displayed will reset it.
To display the odometer reading with the ignition off,
press the reset button.
Engine Hour Meter Display
The odometer can also display the number of hours the
engine has run. To display the hour meter, turn the
ignition off, press and hold the reset button for at least
four seconds. The hour meter will be displayed for
up to 30 seconds, or until the ignition is turned on.
Tachometer
Your tachometer displays the engine speed in
revolutions per minute (rpm).
Notice:If you operate the engine with the
tachometer in the shaded warning area, your vehicle
could be damaged, and the damages would not
be covered by your warranty. Do not operate
the engine with the tachometer in the shaded
warning area.
3-35

Safety Belt Reminder Light
When the key is turned to RUN or START, a chime will
come on for several seconds to remind people to
fasten their safety belts, unless the driver's safety belt is
already buckled.
The safety belt light will
also come on and stay on
for several seconds, then it
will ¯ash for several more.
If the driver's belt is already buckled, neither the chime
nor the light will come on.
Air Bag Readiness Light
There is an air bag readiness light on the instrument
panel cluster, which shows the air bag symbol.
The system checks the air bag's electrical system for
malfunctions. The light tells you if there is an electrical
problem. The system check includes the air bag
sensors, the air bag modules, the passenger sensing
system (if equipped), the wiring and the crash sensing
and diagnostic module. For more information on the
air bag system, see
Air Bag Systems on page 1-70.
This light will come on
when you start your
vehicle, and it will ¯ash for
a few seconds. Then
the light should go out.
This means the system is
ready.
If the air bag readiness light stays on after you start the
vehicle or comes on when you are driving, your air
bag system may not work properly. Have your vehicle
serviced right away.
3-36