2003 GMC SIERRA DENALI cooling

Climate Controls
Dual Automatic Climate Control
System
Your vehicle may have the optional dual automatic
climate control system. With this system you can control
the heating, cooling and ventilation for your vehicle.
If your vehicle is equipped with the dual automatic
climate control system, memory seats, and memory
mirrors, you can store and recall the climate control
settings for temperature, air delivery mode, and
fan speed for two different drivers. The personal choice
settings recalled are determined by the transmitter
used to enter the vehicle. After the button with the
unlock symbol on a remote keyless entry transmitter
is pressed, the climate control will adjust to the last
settings of the identified driver. The settings can also be
changed by pressing one of the memory buttons
(1 or 2) located on the driver’s door. When adjustments
are made, the new settings are automatically saved
for that driver.
A 8fj? v (Fan): Press this button to increase or
decrease the fan speed.
0 (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 floor. 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.
,% 4d (Mode): Press this button to manually select the air
delivery mode to the floor, panel, or windshield outlets.
This system will stay in the selected mode until the mode
button is pressed again, or the AUTO button, defrost
button, or the off button is pressed. Air delivery mode can
be adjusted while the system is off. A five second status
display will indicate the current mode.
3-1 8

2. Set the driver’s and passenger’s temperature.
To find your comfort setting, start with a
74°F
(23°C) temperature setting and allow about
20 minutes for the system to regulate. Turn the
driver’s or passenger’s side temperature knob
to adjust the temperature setting as necessary. If
you choose the temperature setting of
60°F
(15°C) the system will remain at the maximum
cooling setting. If you choose the temperature
setting of
90°F (32°C) the system will remain at the
maximum heat setting. Choosing either maximum
setting will not cause the vehicle to heat or cool any
faster.
Be careful not
to cover the sensor located on the
top of the instrument panel near the windshield.
This sensor regulates air temperature based on sun
load, and also turns on your headlamps.
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 engine coolant temperature. Pressing the fan switch will override this delay and change the fan
to
a selected speed.
Manual Operation
To change the current setting, select one of the
following:
A 8f? v (Fan): This button allows you to manually
adjust the fan speed. Press the up arrow
to increase fan
speed and the down arrow
to decrease fan speed.
4d (Mode): Press this button to manually change the
direction of the airflow in your vehicle; keep pressing the
button until the desired mode appears on the display.
If you press the mode button
to select an air delivery
mode, the display will change
to show you the selected
air mode delivery. The display will then show the
current status of the system. When the system is turned
off, the display will go blank after displaying the
current status
of the system.
f;’ (Vent): This mode directs air to the instrument
panel vents.
+2 (Bi-Level): This mode directs half of the air to the
instrument panel vents, then directs the remaining air
to
the floor vents. A little air is directed toward the
windshield and the side window vents. Cooler air is
directed
to the upper vents and warmer air to the floor
vents.
3-20

Engine Coolant Temperature Gage Transmission Temperature Gage
I I
United States
Canada
This gage shows the engine coolant temperature.
It also provides an indicator of how hard your vehicle is
working. During a majority
of the operation, the gage
will read 210°F
(1 00°C) or less. If you are pulling a load
or going up hills, it is normal for the temperature to
fluctuate and approach the 250°F (122°C) mark.
If the
gage reaches the 260°F
(1 25°C) mark, it indicates
that the cooling system is working beyond its capacity.
See
Engine Overheating on page 5-27.
United States Canada
Your vehicle may be equipped with a transmission
temperature gage.
When your ignition is on, the gage shows the
temperature of the transmission fluid. The normal
operating range is from 100°F (38°C)
to about
265°F
(1 30°C).
At approximately 265°F (13O"C), the message center
will display
a TRANSMISSION HOT message and
the transmission will enter
a transmission protection
mode. When the transmission enters the protection
mode, you may notice a change in the transmission
shifting patterns. The transmission will return to normal
shifting patterns when the transmission fluid temperature
falls below 260°F
(1 27°C).
3-36

CHANGE ENGINE OIL
This message is displayed when the engine oil needs to
be changed.
When you change the engine oil, be sure to reset the
CHANGE ENGINE
OIL message. See Engine Oil, When
to Change
under Engine Oil on page 5-13.
OIL LIFE RESET
This message will appear on the display for about 10
seconds after resetting the change engine oil message.
LOW COOLANT LEVEL
If the engine coolant level is low, this message will
appear on the DIC. Adding coolant will clear the
message.
ENGINE COOLANT HOT
If the cooling system temperature gets hot, this message
will appear in the DIC. Stop the vehicle and let the
engine idle in PARK (P) to allow the coolant to reach a
safe temperature. This message will clear when the
coolant temperature drops to safe operating
temperature.
ENGINE OVERHEATED
If the engine cooling system reaches unsafe
temperatures for operation, this message will appear in
the DIC and you will hear a chime. Stop and turn
off
3-54
the vehicle as soon as it is safe to do so to avoid
severe damage. This message will clear when the
engine has cooled to a safe operating temperature.
OIL PRESSURE LOW
If low oil pressure levels occur, this message will be
displayed on the DIC and a chime will sound. Stop the
vehicle as soon as safely possible and do not operate
it until the cause of the low oil pressure has been
corrected. Check your oil as soon as possible and have
your vehicle serviced.
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
Engine Overheating on page 5-27 for further
information.
BATTERY NOT CHARGING
if the battery is not charging during operation, this
message will appear on the DIC. Driving with this
problem could drain your battery. Have the electrical
system checked as soon as possible. Pressing the
select button will acknowledge this message and clear it
from the DIC display.

If the water isn’t too deep, drive slowly through it. At
faster speeds, water splashes on your ignition system
and your vehicle can stall. Stalling can also occur
if you
get your tailpipe under water. And, as long as your
tailpipe is under water, you’ll never be able to start your
engine. When you go through water, remember that
when your brakes get wet, it may take you longer
+- stop.
,,jving thr,,gh rushing water can be
dangerous. Deep water can sweep your vehicle
downstream and you and your passengers
could drown. If it’s only shallow water, it can
still wash away the ground from under your
tires, and you could lose traction and roll the
water.
~ vehicle over. Don’t drive through rushing
I
After Off-Road Driving
Remove any brush or debris that has collected on the
underbody, chassis or under the hood. These
accumulations can be a fire hazard.
After operation
in mud or sand, have the brake linings
cleaned and checked. These substances can cause
glazing and uneven braking. Check the body structure,
steering, suspension, wheels, tires and exhaust
system for damage. Also, check the fuel lines and
cooling system for any leakage.
Your vehicle will require more frequent service due
to
off-road use. Refer to the Maintenance Schedule
for additional information.
See
Driving in Rain and on Wet Roads on page 4-30 for
more information on driving through water.
4-28

If you drive regularly in steep country, or if you’re
planning to visit there, here are some tips that can make
your trips safer and more enjoyable. See
Operating
Your All-Wheel-Drive Vehicle
Off Paved Roads on
page
4-16 for information about driving off-road.
Keep your vehicle in good shape. Check all fluid
levels and also the brakes, tires, cooling system
and transmission. These parts can work hard
on mountain roads.
Know how to go down hills. The most important
thing to know is this: let your engine do some of
the slowing down. Shift to a lower gear when you go
down a steep or long hill.
If you don’t I R down, your -____ 3s COL- ge-
so hot that they wouldn’t work well. You would
then have poor braking or even none going
down a hill. You could crash. Shift down to let
your engine assist your brakes on a steep downhill slope. Coasting
UVwnlll..
..I NEUTRAL (N) G. .... h the
ignition
off is dangerous. Your brakes will have
to do all the work
of slowing down. They could
get
so hot that they wouldn’t work well. You
would then have poor braking or even none
going down a
hill. You could crash. Always
have your engine running and your vehicle in
gear when you go downhill.
Know how to go uphill. You may want to shift down to
a lower gear. The lower gears help cool your engine
and transmission, and you can climb the hill better.
roads in hills or mountains. Don’t swing wide or cut
across the center of the road. Drive at speeds that let
you stay in your own lane.
As you go over the top of a hill, be alert. There could
be something in your lane, like a stalled car or an
accident.
You may see highway signs on mountains that warn
of special problems. Examples are long grades,
passing or no-passing zones, a falling rocks area or
winding roads. Be alert to these and take appropriate
action.
Stay in your own lane when driving on two-lane
4-37

When You Are Ready to Leave After
Parking on a
Hill
1. Apply your regular brakes and hold the pedal down
while you:
0 start your engine,
shift into a gear, and
0 release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the
chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you’re
pulling a trailer. See the Maintenance Schedule for more
on this. Things that are especially important in trailer
operation are automatic transmission fluid (don’t overfill),
engine
oil, axle lubricant, belt, cooling system and
brake system. Each of these is covered in this manual,
and the Index will help you find them quickly. If
you’re trailering, it’s a good idea to review these sections
before you start your trip.
Check periodically to see that all hitch nuts and bolts
are tight.
4-59

Section 5 Service and Appearance Care
Service ............................................................ 5.3
Doing Your Own Service Work
......................... 5-4
Adding Equipment to the Outside
of Your Vehicle
........................................... 5-4
Fuel
................................................................ 5.5
Gasoline Octane
............................................ 5.5
Gasoline Specifications
.................................... 5.5
California Fuel
............................................... 5.6
Additives
....................................................... 5.6
Fuels in Foreign Countries
................. ....... 5.7
Filling Your Tank
......................................... 5-7
Filling a Portable Fuel Container
.................... 5-9
the Hood
............................................. 5.10
Hood Release
........................................ ,.5-10
Engine Compartment Overview
....................... 5.12
Checking
Things Under
Engine Oil
................................................... 5.13
Engine Air Cleaner/Filter
................................ 5.19
Engine Coolant
............................................. 5.24
Engine Overheating
....................................... 5.27
Cooling System
............................................ 5.30
Automatic
Transmission Fluid
........................ -5-21
Coolant Surge Tank Pressure Cap
.................. 5-27 Engine
Fan Noise
......................................... 5.36
Power Steering Fluid
..................................... 5.37
Windshield Washer Fluid
................................ 5-38
Brakes
........................................................ 5.39
Battery
........................................................ 5.42
Jump Starting
............................................... 5.43
All-Wheel Drive
......................... .............. 5-49
Rear Axle
....................................................... 5-50
Front Axle
...................................................... 5-51
Bulb Replacement
.......................................... 5-52
Halogen Bulbs
.............................................. 5-52
Headlamps
................................................. -5-52
Roof Marker Lamps
...................................... 5-54
Cargo Lamp
............................................. 5-56
Taillamps
..................................................... 5-58
Replacement Bulbs
....................................... 5-59
Front
Turn Signal, Sidemarker
and Daytime
Running Lamps
......................................... 5-53
Center High-Mounted Stoplamp (CHMSL) and
Pickup
Box Identification and Fender Marker
Lamps
..................................................... 5-58
Windshield Wiper Blade Replacement
.............. 5-60
5-
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