light GMC SIERRA 2003 Service Manual

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:Don’t use a razor blade or something else
sharp on the inside of the rear window. If you
do, you could cut or damage the defogger and the
repairs would not be covered by your warranty.
Do not attach a temporary vehicle license, tape, a
decal or anything similar to the defogger grid.
Outlet Adjustment
Use the air outlets located in the center and on the side
of your instrument panel to direct the airflow.
Your vehicle has air outlets that allow you to adjust the
direction and amount of airflow 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 airflow and temperature control, keep
the outlet in the fully opened position.
Rear seat outlets can be used to adjust airflow toward
either seating area, thefloor or upward. Move the center
louvers up or down to direct the airflow.
3-23
2003 - Sierra Denali

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 deflectors, 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
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 briefly 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 3-42.
3-24
2003 - Sierra Denali

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 willflash 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, seeAir Bag Systems on page 1-55.
This light will come on
when you start your
vehicle, and it willflash 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.
3-27
2003 - Sierra Denali

Air Bag Off Light
When you turn the right front passenger’s air bag off,
this light will be lit and stay lit to remind you that the air
bag has been turned off. This light will go off when
you turn the air bag back on again. SeeAir Bag
Off Switch on page 1-61for more on this, including
important safety information.The AIR BAG OFF light will
look like one of the following illustrations.
United States with Passenger Sensing System
3-28
2003 - Sierra Denali

{CAUTION:
If the air bag readiness light ever comes on
when you have turned off the air bag, it means
that something may be wrong with the air bag
system. The right front passenger’s air bag
could inate even though the switch is off. If
this ever happens, don’t let anyone whom the
national government has identied as a
member of a passenger air bag risk group sit
in the right front passenger’s position (for
example, don’t secure a rear-facing child
restraint in your vehicle) until you have your
vehicle serviced.
Passenger Air Bag Status Indicator
If your vehicle has the passenger sensing system
your rearview mirror will have a passenger air bag status
indicator.
When the ignition key is turned to RUN or START, the
passenger air bag status indicator will light ON and
OFF, or the symbol for on and off, for several seconds
as a system check. Then, after several more seconds,Passenger Air Bag Status Indicator–United States
Passenger Air Bag Status Indicator–Canada
3-31
2003 - Sierra Denali

the status indicator will light either ON or OFF, or either
the on or off symbol to let you know the status of the
right front passenger’s frontal air bag.
If the word ON or the on symbol is lit on the passenger
air bag status indicator, it means that the right front
passenger’s frontal air bag is enabled (may inflate).
{CAUTION:
If the on indicator comes on when you have a
rear-facing child restraint installed in the right
front passenger’s seat, it means that the
passenger sensing system has not turned off
the passenger’s frontal air bag. A child in a
rear-facing child restraint can be seriously
injured or killed if the right front passenger’s
air bag inates. This is because the back of
the rear-facing child restraint would be very
close to the inating air bag. Don’t use a
rear-facing child restraint in the right front
passenger’s seat unless the air bag has been
turned off.If the word OFF or the off symbol is lit on the passenger
air bag status indicator, it means that the passenger
sensing system or the air bag off switch has turned off
the right front passenger’s air bag. SeePassenger
Sensing System on page 1-66orAir Bag Off Switch on
page 1-61for more on this, including important safety
information.
{CAUTION:
If the right front passenger’s air bag is turned
off for a person who isn’t in a risk group
identied by the national government, that
person won’t have the extra protection of an
air bag. In a crash, the air bag wouldn’t be able
to inate and help protect the person sitting
there. Don’t turn off the passenger’s air bag
unless the person sitting there is in a risk
group. See″Air Bag Off Switch″in the Index
for more on this, including important safety
information.
If, after several seconds, all status indicator lights
remain on, or if there are no lights at all, there may be a
problem with the lights or the passenger sensing
system. See your dealer for service.
3-32
2003 - Sierra Denali

{CAUTION:
If the air bag off indicator and the air bag
readiness light ever come on together, it
means that something may be wrong with the
air bag system. If this ever happens, have the
vehicle serviced promptly, because an
adult-size person sitting in the right front
passenger seat may not have the protection of
the air bag. See″Air Bag Readiness Light″in
the Index.
Battery Warning Light
If this light is displayed
when the engine is
running, you may have a
problem with your charging
system.
The battery display will also stay on while the key is in
RUN until the engine is started.If the light stays on after starting the engine it could
indicate a problem with the generator drive belt, or some
other charging system problem. Have it checked right
away. Driving with this light displayed could drain
your battery.
If you must drive a short distance with this light
displayed, it helps to turn off all your accessories, such
as the radio and the air conditioner.
Voltmeter Gage
When your engine is not running, but the ignition is in
RUN, this gage shows your battery’s state of charge in
DC volts.
When the engine is running, the gage shows the
condition of the charging system. Readings between the
low and high warning zones indicate the normal
operating range.
3-33
2003 - Sierra Denali

Readings in the low warning zone may occur when a
large number of electrical accessories are operating in
the vehicle and the engine is left at an idle for an
extended period. This condition is normal since the
charging system is not able to provide full power
at engine idle. As engine speeds are increased, this
condition should correct itself as higher engine speeds
allow the charging system to create maximum power.
You can only drive for a short time with the reading
in either warning zone. If you must drive, turn off
all unnecessary accessories.
Readings in either warning zone indicate a possible
problem in the electrical system. Have the vehicle
serviced as soon as possible.
Brake System Warning Light
With the ignition on, the brake system warning light will
flash when you set the parking brake. The light will
flash if the parking brake doesn’t release fully. If you try
to drive with the parking brake engaged, a chime will
sound when the vehicle speed is greater than
3 mph (5 km/h).Your vehicle’s hydraulic brake system is divided into two
parts. If one part isn’t working, the other part can still
work and stop you. For good braking, though, you need
both parts working well.
If the warning light comes on and a chime sounds there
could be a brake problem. Have your brake system
inspected right away.
This light should come on briefly when you turn the
ignition key to RUN. If it doesn’t come on then, have it
fixed so it will be ready to warn you if there’sa
problem.United States
Canada
3-34
2003 - Sierra Denali

If the light comes on while you are driving, pull off the
road and stop carefully. You may notice that the pedal is
harder to push. Or, the pedal may go closer to the
floor. It may take longer to stop. If the light is still on,
have the vehicle towed for service. SeeTowing
Your Vehicle on page 4-46.
{CAUTION:
Your brake system may not be working
properly if the brake system warning light is
on. Driving with the brake system warning light
on can lead to an accident. If the light is still
on after you’ve pulled off the road and stopped
carefully, have the vehicle towed for service.
Anti-Lock Brake System Warning
Light
With the anti-lock brake
system, this light will come
on when you start your
engine and may stay on for
several seconds.
That’s normal. If the light doesn’t come on then, have it
fixed so it will be ready to warn you if there is a
problem.
If the light stays on, or comes on when you’re driving,
your vehicle needs service. You will also hear a
chime sound when the light is on steady. If the regular
brake system warning light isn’t on, you still have
brakes, but you don’t have anti-lock brakes. If the
regular brake system warning light is also on you don’t
have anti-lock brakes and there’s a problem with
your regular brakes. In addition to both lights, you will
also hear a chime sound on thefirst occurrence of
a problem and each time the vehicle is shut off and then
restarted. SeeBrake System Warning Light on
page 3-34.
3-35
2003 - Sierra Denali

SeeDriver Information Center (DIC) on page 3-42for
further information.
If the transmissionfluid reaches temperatures of
approximately 275°F (135°C) or greater, the Driver
Information Center will display a TRANS HOT IDLE
ENG warning message. Pull the vehicle off the roadway
when it is safe to do so. Set the parking brake, place
the transmission in PARK (P) and allow the engine
to idle until the transmission temperature falls below
260°F (127°C). If the transmission continues to operate
above 265°F (130°C), contact your nearest dealer or
the GM Roadside Assistance Center. SeeRoadside
Assistance Program on page 7-5.
Notice:If you keep driving your vehicle with the
transmission temperature gage above the normal
operating range, you can damage the transmission.
This could lead to costly repairs that may not be
covered under your warranty.
The following situations can cause the transmission to
operate at higher temperatures:
•Towing a trailer
•Hot outside air temperatures
•Hauling a large or heavy load
•Low transmissionfluid level
•High transmissionfluid level
•Restricted airflow to the radiator and the auxiliary
transmission oil cooler (if equipped).A temporary solution to hotter transmission operating
temperatures may be to let the transmission cool down.
If the transmission is operated at higher temperatures
on a frequent basis, seeScheduled Maintenance
on page 6-5for the proper transmission maintenance
intervals.
Malfunction Indicator Lamp
Check Engine Light
Your vehicle is equipped
with a computer which
monitors operation of the
fuel, ignition and emission
control systems.
This system is called OBD II (On-Board
Diagnostics-Second Generation) and is intended to
assure that emissions are at acceptable levels for the
life of the vehicle, helping to produce a cleaner
environment. The Check Engine light comes on to
indicate that there is a problem and service is required.
Malfunctions often will be indicated by the system
before any problem is apparent. This may prevent more
serious damage to your vehicle. This system is also
designed to assist your service technician in correctly
diagnosing any malfunction.
3-37
2003 - Sierra Denali