
Cold Weather Starting
If your vehicle has the DURAMAX®Diesel Engine, the
following notice applies:
Notice:Your diesel engine has an electric air
intake heater system which reduces white smoke
and helps start the engine in cold weather. Do
not spray starting uid into the air intake where it
can contact the heater elements.
If you do not have the GM Automatic Ether Injection
System, do not use starting uid or you could
damage your engine. If you have the GM system,
use only GM approved starting uid that has
been tested to establish compatibility with the air
inlet heater system.The following tips will help you get good starting in cold
weather.•Use the recommended engine oil when the outside
temperature drops below freezing. SeeEngine Oil
(Caterpillar
®Diesel Engine) on page 5-24or
Engine Oil (DURAMAX®Diesel) on page 5-24or
Engine Oil (Gasoline Engine) on page 5-28.
When the outside temperature drops below
0°F (−18°C), use of the optional engine coolant
block heater is recommended.
•If you experience longer cranking times, notice
an unusual amount of exhaust smoke or are at
higher altitudes (over 7,000 ft. or 2 135 m), you may
use your optional engine coolant block heater.
SeeEngine Coolant Heater on page 2-26.
•SeeWhat Fuel to Use on page 5-8for information
on what fuel to use in cold weather.
2-17

Diesel Engine Exhaust Brake
If your vehicle has a DURAMAX®7800 or Caterpillar®
diesel engine, it may have an exhaust brake, which
is located in the exhaust system.
If your vehicle has a 6.6L DURAMAX
®6600 diesel
engine, it may have an exhaust brake, which is
controlled through the turbocharger.
The exhaust brake for both engines operates the same.
The exhaust brake switch
is located in the instrument
panel switchbank.
Push the bottom of the switch to turn the exhaust brake
on. When you push the top of the switch, the exhaust
brake will turn off.
There is an indicator light on the instrument panel
similar to the symbol on the switch, that will come on
when the exhaust brake is active. SeeExhaust
Brake Indicator Light on page 3-41for more information.When using the exhaust brake, the proper gear range
selection is important. The exhaust brake will be
most effective if the gear range selected is the lowest
possible range that does not allow the engine rpm to go
more than 200 rpm above rated (full load) rpm. If you
have a Caterpillar®diesel engine, do not exceed
2900 rpm. If you have a DURAMAX®7800 diesel
engine, do not exceed 2550 rpm. If you have a
DURAMAX
®6600 diesel engine, do not exceed
3600 rpm.
If your vehicle has an Allison
®1000/2200/2300/2500
series automatic transmission and press this button, the
transmission will downshift to a factory default setting
of third gear. To change the default setting, or for more
information on factory default settings, contact your
dealer for assistance.
The accelerator and clutch pedals must be released in
order for the exhaust brake to engage. The exhaust
brake will automatically shut off when the anti-lock brake
system is active.
If your vehicle has a Caterpillar
®diesel engine or a
DURAMAX®6600 diesel engine, the exhaust brake will
become active in cruise control when you exceed
the set speed by 3 to 5 mph.
2-27

Locking Hubs
Turn the dial of the hublock (A) from the “Free” position
to the “Lock” position to lock the front axle.
Turn the dial of the hublock (A) from the “Lock” position
to the “Free” position to unlock the axle.
You do not have to back the vehicle up to disengage
the hublocks.If your vehicle is equipped
with four-wheel drive, the
transfer case knob is
located to the right of the
steering wheel on the
instrument panel. Use this
knob to shift into and
out of four-wheel drive.
An indicator light will show you which position the
transfer case is in. The indicator lights will come on
briefly when you turn on the ignition and one will stay on.
If the lights do not come on, you should take your
vehicle to your dealer for service. An indicator light will
flash while shifting the transfer case. It will remain
illuminated when the shift is complete. If for some
reason the transfer case cannot make a requested shift,
it will return to the last chosen setting. Hublock Dial Location
Hublock Dial
2-36

Recommended Transfer Case Settings
Driving ConditionsTransfer Case Settings
2m4m4nN
Normal YES
Severe YES
Extreme YES
Vehicle in Tow* YES
*SeeTowing Your Vehicle on page 4-37for further
information.
2
m(Two-Wheel High):This setting is for driving in
most street and highway situations. The transfer
case does not drive the front axle in two-wheel drive.
The front-axle will spin if the front wheel hubs are
locked. Be sure to unlock the hubs to achieve the best
fuel economy.
4
m(Four-Wheel High):Use Four-Wheel High when
you need extra traction, such as on snowy or icy
roads or in most off-road situations. Be sure the front
wheel hubs are locked when you want to drive in
Four-Wheel High.4
n(Four-Wheel Low):This setting sends maximum
power to all four wheels. You might choose Four-Wheel
Low if you are driving off-road in deep sand, deep
mud, and climbing or descending steep hills. Be sure
the front wheel hubs are locked when you want to drive
in Four-Wheel Low.
{CAUTION:
Shifting the transfer case to NEUTRAL can
cause your vehicle to roll even if the
transmission is in PARK (P). You or someone
else could be injured. If you are going to leave
your vehicle, set the parking brake and shift
the transmission to PARK (P) and make sure
the transfer case is in a drive gear.
Notice:If your vehicle has an Allison
®transmission
and you try to put the transmission in PARK (P)
while the transfer case is in Four-Wheel Low,
the transmission may not go into PARK (P) and
could damage your vehicle. When parking your
vehicle, make sure the transfer case is in Two-Wheel
High or Four-Wheel High.
NEUTRAL:Shift the vehicle’s transfer case to
NEUTRAL only when towing your vehicle.
2-37

If the knob is turned to Four-Wheel High or Two-Wheel
High when your vehicle is in gear and/or moving, the
Four-Wheel High or Two-Wheel high indicator light
will flash for 30 seconds. It will not complete the shift
unless your vehicle is moving less than 3 mph (5 km/h)
with the transmission in NEUTRAL (N).
Shifting Into NEUTRAL
Before shifting the transfer case to NEUTRAL, first
make sure the vehicle is parked so that it will not roll.
1. Set the parking brake.
2. Start the vehicle.
3. Put the transmission in NEUTRAL (N).
4. Shift the transfer case to Two-Wheel High.
5. Turn the transfer case knob all of the way past
Four-Wheel Low and hold it there for a minimum
of 10 seconds. The neutral indicator light will
come on.
6. Shift the transmission to REVERSE (R) for
one second, then shift the transmission to
DRIVE (D) for one second.
7. Turn the ignition to OFF.
8. Place the transmission shift lever in PARK. (P).
9. Turn the ignition to LOCK.
Shifting Out of NEUTRAL
To shift the transfer case out of NEUTRAL, do the
following:
1. Set the parking brake and apply the regular brake
pedal.
2. Turn the ignition to RUN with the engine off.
3. Put the transmission in NEUTRAL (N).
4. Turn the transfer case knob to the desired shift
position (Two-Wheel High, Four-Wheel High,
Four-Wheel Low).
5. After the transfer case has shifted out of NEUTRAL,
the indicator light will go out.
Notice:Driving with the parking brake on can
overheat the brake system and cause premature
wear or damage to brake system parts. Verify that
the parking brake is fully released and the brake
warning light is off before driving.
6. Release the parking brake.
7. Start the engine and shift the transmission lever to
the desired position.
Excessively shifting the transfer case into or out of the
different modes may cause the transfer case to enter the
shift protection mode. This will protect the transfer case
from possible damage and will only allow the transfer
case to respond to one shift per 10 seconds. The transfer
case may stay in this mode for up to three minutes.
2-39

Mirrors
Manual Rearview Mirror
If your vehicle has this feature, pull the tab under the
mirror toward you to reduce glare from headlamps
behind you after dark. Push the tab away from you to
restore the mirror to the daytime position.
Outside Manual Mirrors
Adjust the outside rearview mirrors so you can see a
little of the side of your vehicle, and the area beside your
vehicle from a comfortable driving position. All mirrors
can be folded in to enter narrow passageways.
Outside Power Mirrors
If you have outside power mirrors, they can be adjusted
from the inside of the vehicle.
The control for this
feature is located on the
driver’s door.
Select the mirror you want to move by turning the
switch clockwise to adjust the passenger’s side mirror,
or counterclockwise to adjust the driver’s side mirror.
The center position is neutral.
Then, adjust the mirror by pressing the outer arrows on
the switch until the mirror is in the desired position.
2-47

Storage Areas
Your vehicle includes a number of storage
compartments.
Some vehicles have storage areas in the instrument
panel. Another small storage area may be located
overhead. Other models may have more storage area
underneath the front passenger’s bench seat. Lift
the seat cushion to use the storage area.
Your vehicle may have a storage tray located behind
the driver and passenger seats.
All models have storage pockets and cupholders on
each of the doors. Some models may have additional
cupholders in the center floor console.
All models also have storage compartments located
beneath the floorboard on both sides of the vehicle.
Center Console Storage Area
Your vehicle may have a center console compartment if
you have the bucket or suspension seats.
The back of your center bench seat may also fold
forward to reveal a console compartment.
The release strap for the
center console is located
between the center
seat and passenger’s seat.
To expose the storage compartment, pull the strap to
release the seatback. Then fold the seatback forward.
To open the storage compartment, press the release
button and lift the lid rearward. With the lid closed, it can
be used as a clipboard to hold papers in place.
Before returning the seatback to the upright position,
make sure the console is snapped shut. Lift the seatback
all the way up until it clicks. Push and pull on the seatback
to make sure the seat is locked in place.
2-49

Instrument Panel Overview...............................3-4
Hazard Warning Flashers................................3-6
Other Warning Devices...................................3-6
Horn .............................................................3-6
Tilt Wheel.....................................................3-7
Turn Signal/Multifunction Lever.........................3-7
Turn and Lane-Change Signals........................3-8
Headlamp High/Low-Beam Changer..................3-8
Windshield Wipers..........................................3-9
Windshield Washer.......................................3-10
Cruise Control..............................................3-10
Exterior Lamps.............................................3-14
Headlamps on Reminder................................3-15
Daytime Running Lamps (DRL).......................3-15
Marker Lamps..............................................3-16
Instrument Panel Brightness...........................3-16
Dome Lamps ...............................................3-16
Entry Lighting...............................................3-17
Reading Lamps............................................3-17
Instrument Panel Switchbank..........................3-18
Accessory Power Outlet(s).............................3-19
Ashtray(s) and Cigarette Lighter......................3-20Climate Controls............................................3-20
Climate Control System.................................3-20
Outlet Adjustment.........................................3-24
Rear Heating System....................................3-24
Warning Lights, Gages, and Indicators............3-25
Instrument Panel Cluster................................3-26
Speedometer and Odometer...........................3-27
Trip Odometer..............................................3-27
Tachometer.................................................3-27
Engine Speed Limiter....................................3-28
Safety Belt Reminder Light.............................3-28
Safety Belt Reminder Tone............................3-28
Airbag Readiness Light..................................3-29
Airbag Off Light............................................3-30
Charging System Light..................................3-31
Voltmeter Gage............................................3-32
Service Transmission Warning Light................3-32
Range Inhibit Warning Indicator......................3-33
Brake System Warning Light..........................3-33
Anti-Lock Brake System Warning Light.............3-35
Trailer Anti-Lock Brake System Warning Light . . .3-36
Engine Coolant Temperature Gage..................3-36
Section 3 Instrument Panel
3-1