2003 GMC SIERRA DENALI tow

Outlet Adjustment Operation Tips
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.
If your vehicle is equipped with rear seat outlets they
can be used
to adjust airflow toward either seating area,
the floor, or upward. Move the center louver up or
down
to direct the airflow. 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.
3-23

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.
I BRAKE I
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United States Canada
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’s a problem.
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. See Towing
Your Vehicle on page 4-45.
3-34

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.
, I
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 the first occurrence of
a problem and each time the car is shut
off and then
restarted. See
Brake System Warning Light on
page 3-34 earlier in this section.
3-35

See Driver Information Center (DIC) on page 3-43 for
further information.
If the transmission fluid reaches temperatures of
approximately 275°F
(1 35°C) or greater, the Driver
Information Center wiil 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 (1 27°C). If the transmission continues to operate
above
265°F (13O"C), contact your nearest dealer or
the
GM Roadside Assistance Center. See Roadside
Assistance Program
on page 7-5.
Notices 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:
0 Towing a trailer
0 Hot outside air temperatures
0 Hauling a large or heavy load
0 Low transmission fluid level
High transmission fluid level
0 Restricted air flow 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, see
Scheduled Maintenance
on page
6-5 for the proper transmission maintenance
intervals.
3-37

If the Light is Flashing
The following may prevent more serious damage to
your vehicle:
Reducing vehicle speed.
Avoiding hard accelerations.
0 Avoiding steep uphill grades.
If you are towing a trailer, reduce the amount of
cargo being hauled as soon as it is possible.
If the light stops flashing and remains on steady, see “If
the Light
Is On Steady” following.
If the light continues to flash, when it is safe to do
so,
stop the vehicle. Find a safe place to park your vehicle.
Turn the key
off, wait at least 10 seconds and restart
the engine. If the light remains on steady, see
“If
the Light Is On Steady” following. If the light is still
flashing, follow the previous steps, and drive the vehicle
to your dealer or qualified service center for service.
If the Light Is On Steady
You may be able to correct the emission system
malfunction by considering the following:
Did you recently put fuel into your vehicle?
If
so, reinstall the fuel cap, making sure to fully install
the cap. See
Fi//ing Your Tank on page 5-7. The
diagnostic system can determine
if the fuel cap has
been left
off or improperly installed. A loose or missing fuel
cap will allow fuel to evaporate into the atmosphere.
A few driving trips with the cap properly installed
should turn the light
off.
Did you just drive through a deep puddle of water?
If so, your electrical system may be wet. The condition
will usually be corrected when the electrical system
dries out. A few driving trips should turn the light
off.
Have you recently changed brands of fuel?
If
so, be sure to fuel your vehicle with quality fuel. See
Gasoline Octane on page 5-5. Poor fuel quality will
cause your engine not to run
as efficiently as designed.
You may notice this as stalling after start-up, stalling
when you put the vehicle into gear, misfiring, hesitation
on acceleration or stumbling on acceleration. (These
conditions may go away once the engine is warmed up.)
This will be detected by the system and cause the
light to turn on.
If you experience one or more of these conditions,
change the fuel brand you use. It will require at least
one full tank of the proper fuel to turn the light off.
If none of the above steps have made the light turn off,
have your dealer or qualified service center check
the vehicle. Your dealer has the proper test equipment
and diagnostic tools to
fix any mechanical or electrical
problems that may have developed.
3-39

A reading in the low pressure zone may be caused by a
dangerously low oil level or some other problem
causing
low oil pressure. Check your oil as soon as
possible. See
DIC Warnings and Messages on
page 3-53
and ‘vgine Oil on page 5-13.
Don’t keep driving if the oil pressure is low. If
you do, your engine can become
so hot that it
catches fire. You or others could be burned.
Check your oil as soon as possible and have
your vehicle serviced.
Notice: Damage to your engine from neglected oil
problems can be costly and is not covered by
your warranty.
Cruise Control Light
The cruise light comes on
whenever you set your
cruise control. See “Cruise
Control” under
Turn
SignaVMultifunction Lever
on page 3-5.
Tow/HauI Mode Light
This light is displayed
when the tow/haul mode
has been activated.
For more information, see
Towing a Trailer on
page 4-5
I.
3-41

SERVICE AIRBAG
If there is a problem with the air bag system, this
message will be displayed on the
DIC. Have a qualified
technician inspect the system for problems. Pressing
the select button will acknowledge this message
and clear it from the
DIC display.
SERVICE BRAKE SYSTEM
If there is a problem with the brake system, this
message will be displayed on the
DIC. If this message
appears, stop as soon as possible and turn
off the
vehicle. Restart the vehicle and check for the message
on the
DIC display. If the message is still displayed,
or appears again when you begin driving, the brake
system needs service.
SERVICE BRAKE BOOSTER
If your vehicle has vaccum assist power brakes, this
message will be displayed on the
DIC when there is a
problem with the Supplemental Brake Assist system.
If the message is displayed immediately after starting
the vehicle or the message appears while driving,
your Supplemental Brake Assist system needs service.
See
Brake System Warning Light on page 3-34.
Your brake system may not be working
properly if the SERVICE BRAKE BOOSTER
message is displayed.
If the brake system warning light is also on,
you should have the vehicle towed for service. See “Brake System Warning Light”
in the
Index.
If the brake system warning light
isn’t on, you
still have brakes, but the supplemental brake
assist system may not operate properly.
In the
event of a vacuum
loss, you may not have
vacuum power assist for braking. The brake pedal will
be harder to push and it will take
longer to stop.
If you continue to drive with
this message displayed it can lead to a crash.
Have the brake system serviced as soon as
possible.
3-55

REDUCED BRAKE POWER
If your vehicle has vacuum assist power brakes, this
message will be displayed and you may notice that the
brake pedal is harder to push and it will take longer
to stop. You may also hear a motor running and feel a
slight vibration in the brake pedal or steering wheel
when you apply or release the brake pedal even
if your
foot is not on the brake pedal. This indicates that the
Supplemental Brake Assist system is working to
maintain braking power.
If you are braking lightly, you
may not notice any difference in the operation
of
your brakes.
This message may also be displayed for brief periods
if
you are driving at higher elevations and are pumping
your brakes or braking hard. The message may
clear after you’ve lifted your foot from the accelerator
pedal an allowed the vehicle to coast
in gear or after you
have driven down to a lower elevation. This is a
normal operation of your brake system and does not
require that the brake system be serviced. However,
if
the message does not clear, your brake system
needs service. While the message is displayed you will
notice that the brake pedal is harder to push and
it
will take longer to stop. See Brake System Warning
Light
on page 3-34.
Your brake system may not be working
properly if the REDUCED BRAKE POWER
message is displayed. If this message comes
on and stays on while driving, pull
off the road
and stop carefully. The brake pedal will be
harder to push and
it will take longer to stop.
If the message is no longer displayed after you
have pulled
off the road and stopped, you can
continue driving.
However, if the message is still displayed, or if
it comes on again when you are driving, there
is a problem with your brake system. If you
continue to drive with this message displayed
it can lead to an accident. You should have the
vehicle towed for service. Also, see Brake
System Warning Light in the Index.
3-57