
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 Outlets...............................3-19
Ashtrays and Cigarette Lighter........................3-20
Climate Controls............................................3-20
Climate Control System.................................3-20
Outlet Adjustment.........................................3-23
Rear Heating System....................................3-24Warning Lights, Gages, and Indicators............3-24
Instrument Panel Cluster................................3-25
Speedometer and Odometer...........................3-26
Trip Odometer..............................................3-26
Tachometer.................................................3-26
Engine Speed Limiter....................................3-26
Safety Belt Reminder Light.............................3-27
Safety Belt Reminder Tone............................3-27
Airbag Readiness Light..................................3-27
Airbag Off Light............................................3-28
Charging System Light..................................3-30
Voltmeter Gage............................................3-30
Service Transmission Warning Light................3-31
Range Inhibit Warning Indicator......................3-31
Brake System Warning Light..........................3-31
Anti-Lock Brake System Warning Light.............3-34
Trailer Anti-Lock Brake System Warning Light.....3-34
Engine Coolant Temperature Gage..................3-35
Low Coolant Warning Light............................3-35
Wait to Start Indicator (Diesel Engine).............3-36
Malfunction Indicator Lamp.............................3-36
Oil Pressure Gage........................................3-37
Low Oil Level Light.......................................3-38
Change Engine Oil Light................................3-38
Engine Overspeed Warning Light....................3-39
Engine Shutdown Warning Light.....................3-39
Section 3 Instrument Panel
3-1

Transmission Temperature Gage.....................3-39
Exhaust Brake Indicator Light.........................3-40
Differential Lock Indicator Light.......................3-40
Reduced Engine Power Light.........................3-41
Highbeam On Light.......................................3-41
Daytime Running Lamps (DRL) Indicator Light.....3-41
Low Washer Fluid Warning Light.....................3-42
Check Gages Warning Light...........................3-42
Fuel Gage...................................................3-42
Water in Fuel Warning Light...........................3-43
Air Filter Restriction Indicator..........................3-43
Air Pressure Gage........................................3-44
Hourmeter Gage...........................................3-44Audio System(s).............................................3-44
Setting the Time...........................................3-45
AM-FM Radio...............................................3-45
Radio with Cassette......................................3-48
Radio with CD..............................................3-53
Theft-Deterrent Feature (Non-RDS Radios).......3-57
Radio Reception...........................................3-57
Care of the Cassette Tape Player...................3-58
Care of Your CDs.........................................3-59
Care of the CD Player...................................3-59
Fixed Mast Antenna......................................3-59
Chime Level Adjustment................................3-59
Section 3 Instrument Panel
3-2

A. Air Outlets. SeeOutlet Adjustment on page 3-23.
B. Instrument Panel Cluster. SeeInstrument Panel
Cluster on page 3-25.
C. Shift Lever. SeeStarting the Gasoline Engine on
page 2-12orStarting the Diesel Engine on
page 2-14.
D. Air Brake Controls. SeeAir Brake on page 2-40.
E. Transfer Case Controls (If Equipped). See
“Automatic Transfer Case” underFour-Wheel Drive
on page 2-33. Air Filter Gage (If Equipped). See
Air Filter Restriction Indicator on page 3-43.
F. Auxiliary Gages. SeeWarning Lights, Gages, and
Indicators on page 3-24.
G. Exterior Lamp Control. SeeExterior Lamps on
page 3-14.H. Turn Signal/Multifunction Lever. SeeTurn
Signal/Multifunction Lever on page 3-7.
I. Hazard Warning Flashers Button. SeeHazard
Warning Flashers on page 3-6.
J. Audio System(s). SeeAudio System(s) on
page 3-44.
K. Climate Controls. SeeClimate Control System on
page 3-20.
L. Instrument Panel Switchbank. SeeInstrument Panel
Switchbank on page 3-18.
M. Airbag Off Switch. SeeAirbag Off Switch on
page 1-56.
N. Accessory Power Outlets. SeeAccessory Power
Outlets on page 3-19.
3-5

Hazard Warning Flashers
Your hazard warning flashers let you warn others. They
also let police know you have a problem. Your front
and rear turn signal lamps will flash on and off.
The hazard warning
flasher button is located
on top of the steering
column.
Your hazard warning flashers work no matter what
position your key is in, and even if the key is not in
the ignition.
Press the button to make the front and rear turn signal
lamps flash on and off. Press the button again to
turn the flashers off.
When the hazard warning flashers are on, your turn
signals will not work.
Other Warning Devices
If you carry reflective triangles, you can set them up at
the side of the road about 300 feet (100 m) behind
your vehicle.
Horn
Sound the horn by pushing the center of the steering
wheel. If you have the optional air horn, it is controlled
by a cord that you’ll find up above and to the left of
the driver. The harder you pull on the cord, the louder
the air horn will sound. The air horn works only after
your air brake system pressure gets up to about
115 psi (790 kPa). The air horn will work properly
unless the air brake system pressure drops below
60 psi (415 kPa).
3-6

Rear Heating System
If you have a crew cab
and your vehicle has a
rear heater, the
thumbwheel for this
feature is located on
the headliner.
To increase and decrease the flow of heated air to
the rear floor vents, turn the thumbwheel to the
desired fan speed. To turn the fan off, turn the
thumbwheel down.
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.
3-24

Charging System Light
The charging system light
may be located in the
instrument panel cluster, or
with the auxiliary warning
lights in the center of
the instrument panel.
It should come on briefly when you turn on the ignition,
before the engine is running, as a check to show
that it is working.
If it stays on, or comes on while you are driving, have
your vehicle checked right away. You could have a loose
generator drive belt or some other problem.
Driving while this light is on will drain your battery. If you
must drive a short distance with the light on, turn off
your radio and other accessories. Sustained driving with
a generator failure could result in a lack of back-up
braking if the engine quits or the power steering pump
should fail.
Voltmeter Gage
When your engine is
running, the voltmeter
gage shows the charging
system voltage.
Readings in either warning zone indicate a possible
problem in the electrical system.
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 may not be able to provide full
power at engine idle. As engine speeds are increased,
this condition should correct itself because higher
engine speeds allow the charging system to create
maximum power.
You can only drive a short time on the battery. Be sure
to shut off the radio, the fan or any unnecessary
accessories and have the system serviced.
3-30

Service Transmission Warning Light
If your vehicle has an Allison automatic transmission,
certain transmission malfunctions will turn this light on.
This light is located with
the auxiliary warning lights
in the center of the
instrument panel.
If this light comes on while you are driving, do not use
the transmission shift control or you may lose forward
gears. The computer for the transmission senses
a problem and chooses a gear to stay in so that you
can drive the vehicle in that gear. You may not be able
to drive as fast or back up when this light is on.
Notice:If you continue driving your vehicle after
the transmission warning light comes on, you could
damage the transmission. While this light is on,
the transmission cannot operate in all gears. If you
attempt to shift gears, the vehicle may not
continue to move. Do not attempt to shift gears
while the transmission warning light is on. Instead,
drive directly to a GM dealer for service. If you
cannot drive to a dealer immediately, have the
vehicle towed.
Range Inhibit Warning Indicator
If your vehicle has an Allison
1000/2000/2200/2400/2500 series automatic
transmission, a lighted bar under the current gear
selected will flash.
If your vehicle has an Allison 3000/3500 series automatic
transmission, the current gear selected on the pushbutton
display will flash.
The flashing bar or gear selection indicates that
transmission range shifts may not occur.
For detailed information on shift inhibit limitations, see
the Allison Automatic Transmission Operator’s Manual in
your vehicle for further information.
Brake System Warning Light
Your vehicle has either hydraulic or air brakes. Each
system has different warning lights.
3-31

Hydraulic Brake System
Warning Lights
Vehicles with hydraulic brake systems have two brake
system warning lights on the instrument panel.
If the BRAKE system
warning light comes on, it
means that the fluid
level in the master cylinder
reservoir is low or there
is another problem
with your hydraulic brakes.
When it comes on, you will also hear a warning tone.
The BRAKE system warning light may come on, and the
warning tone may sound, when you’re turning and
braking at the same time. This is normal. See “Hydraulic
Brake Systems” underBraking on page 4-5.If the service brakes soon
warning light comes on, it
means there may be
something wrong in the
brake system.
When this light comes on, you will also hear a warning
tone. Have the system repaired immediately.
Both of these lights should come on briefly every time
you start your engine. If they don’t come on then,
have them fixed so they will be ready to warn you if
there’s a problem. If one or both of these warning lights
stay on after you start the engine, there could be a
brake problem. Have your brake system inspected
right away.
If one or both of these lights come 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 BRAKE light is still on, have the vehicle towed for
service. SeeTowing Your Vehicle on page 4-35. See
“Hydraulic Brake Systems” underBraking on page 4-5
for further information.
3-32