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{CAUTION:
If the airbag readiness light ever comes on
when you have turned off the airbag, it means
that something may be wrong with the airbag
system. The right front passenger’s airbag
could in ate even though the switch is off.
If this ever happens, do not let anyone whom
the national government has identi ed as a
member of a passenger airbag risk group
sit in the right front passenger’s position
(for example, do not secure a rear-facing child
restraint in the right front passenger’s seat)
until you have your vehicle serviced. See
Airbag Off Switch on page 1-56andAirbag
Readiness Light on page 3-28for more on this,
including important safety information.
If the word ON or the on symbol is lit, it means that
the right front passenger’s frontal airbag is enabled
(may inflate). SeeAirbag Off Switch on page 1-56for
more on this, including important safety information.
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.
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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.
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 an authorized dealer for service. If you
cannot drive to a dealer immediately, have the
vehicle towed.
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Range Inhibit Warning Indicator
If your vehicle has an Allison 1000/2200/2300/2500 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.
Hydraulic Brake System Warning Lights
Vehicles with hydraulic brake systems have two brake
system warning lights on the instrument panel.
If the brake 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.
This light should come on briefly when you turn the
ignition key to RUN. If it does not come on, then have it
fixed so it will be ready to warn you if there is a problem.
The brake warning light may come on, and the warning
tone may sound, when you are turning and braking
at the same time. This is normal. See “Hydraulic Brake
Systems” underBraking on page 4-4.
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Parking Brake Warning Light
Your vehicle has a brake warning light. When the
ignition is on, this light will come on when you set your
parking brake. The light will stay on if your parking
brake does not release fully.
This light should also come on when you turn the
ignition key to START. If it does not come on then, have
it fixed so it will be ready to remind you if the parking
brake is applied or has not released fully.
Air Brake System Warning Light
Vehicles with air brake systems have a brake system
warning light on the instrument panel.
The low air warning light
should come on, as a
check, whenever you start
the engine.
However, it is designed to come on, and stay on, when
brake reservoir pressure has dropped below 60 psi
(410 kPa).When the warning light comes on while you are driving,
you should drive only as far as the nearest point of
safety and then stop the vehicle. Here is a very
important thing for you to know:
{CAUTION:
If the air brake system warning light comes on
and the warning tone sounds, the vehicle can
stop suddenly and without further warning.
This is because the parking brake will come on
if the pressure falls below 35 to 45 psi (240 to
310 kPa). You or others could be injured. If the
air brake system warning light comes on and
the warning tone sounds, stop as soon as you
can. You will not know how quickly the system
is losing pressure, so be aware that the
parking brake may come on suddenly.
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Wait to Start Indicator
If your vehicle has the DURAMAX®6.6L diesel engine,
it will have glow plugs and an air intake heater.
If your vehicle has the Isuzu 6H diesel engine, it will
have glow plugs and an inlet heater. If your vehicle has
a Caterpillar
®engine, it will have an inlet heater.
The light in the center of
the instrument panel will
come on when the
inlet heater or glow plugs
are on and the ignition
key is in RUN.
Wait until the indicator light goes off before turning the
ignition key to START.
Malfunction Indicator Lamp
Service Engine Soon Light
If this light comes on or
flashes while you are
driving, two things
can happen.
First, you will not notice any difference in engine
performance, but the tail pipe emissions might increase.
Second, the engine might not run properly or could stall
without warning. If either of these things happen, drive or
tow your vehicle to your dealer/retailer for service.
This light should come on when the ignition is on, but the
engine is not running, as a check to show you it is
working. If it does not come on at all, have it repaired.
Notice:If you keep driving your vehicle with this
light on, after a while, the emission controls
might not work as well, your vehicle’s fuel economy
might not be as good, and the engine might not
run as smoothly. This could lead to costly repairs
that might not be covered by your warranty.
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Oil Pressure Gage
The engine oil pressure
gage, on the lower right
portion of your instrument
panel cluster, shows
engine oil pressure in
psi (pounds per square
inch) or in kPa
(kilopascals).
Oil pressure may vary with outside temperature and oil
viscosity, but readings of 30 to 40 psi (205 to 275 kPa)
on gasoline engines at operating temperature and
moderate road speeds are normal. If you have a diesel
engine, the normal operating range should be between
35 and 70 psi (240 to 480 kPa).A reading in the low pressure zone may be caused by a
dangerously low oil level or other problem.
If you have a Caterpillar®diesel engine, also see your
Caterpillar®Operation & Maintenance Manual.
{CAUTION:
Do not keep driving if the oil pressure is low.
If you do, your engine can become so hot that
it catches re. You or others could be burned.
Check your oil as soon as possible and have
your vehicle serviced.
Notice:Lack of proper engine oil maintenance
may damage the engine. The repairs would not be
covered by your warranty. Always follow the
maintenance schedule in this manual for changing
engine oil.
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Engine Overspeed Warning Light
If your vehicle has this
light, it will come on if your
engine is operating at
too many revolutions per
minute (rpm).
It will also come on for a moment as a check when you
start your engine.
If it comes on when you’re driving, reduce your engine
speed immediately.
Engine Shutdown Warning Light
If your vehicle has the
engine shutdown feature,
this light will come on
when engine shutdown
is active.
SeeEngine Alarm and Automatic Shutdown on
page 2-18for more information.
Transmission Temperature Gage
If you have an automatic
transmission and this
gage, it is located
above the switchbank
in the center of the
instrument panel.
When your ignition is on, the gage shows the
temperature of the transmission oil. A reading in the
warning zone, the red area beginning at 300°F (150°C),
means you must stop driving and check into the cause.
One possible cause is a low oil level in the transmission.
Notice:If you drive your vehicle with the
transmission temperature gage above normal
operating range, you can damage the transmission.
This could lead to costly repairs that would not
be covered by your warranty. Do not drive your
vehicle while the transmission temperature gage
reading is above normal. See your dealer for service.
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Exhaust Brake Indicator Light
For vehicles with an
exhaust brake, this light is
located above the
climate controls.
The exhaust brake indicator light will come on and stay
on whenever the diesel engine exhaust brake or
exhaust restrictor is active. For more information,
seeDiesel Engine Exhaust Brake on page 2-26and
Exhaust Restrictor (Engine Warm-Up) on page 2-22.
Differential Lock Indicator Light
If your vehicle has this
feature, this light is
located in the center of
the instrument panel.
The light is on when the
rear differential lock system
is in use.
The light will come on momentarily during starting.
If the light fails to come on, have it repaired as soon as
possible so you will be aware when the lock system
is in use.
SeeRear Axle Differential Lock Control on page 4-7for
more information.
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