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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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Anti-lock Brake System (ABS)
Warning Light
This light will come on
briefly when you start the
engine, then it will turn
off. This is normal.
If the light stays on, or comes on when you are driving,
your vehicle needs service. If the brake or low air
warning light is not on, you still have brakes, but you do
not have the antilock brake feature. If the brake
and/or low air warning light is on, you do not have
antilock brakes and there is a problem with your regular
brakes. SeeBrake System Warning Light on page 3-32
andAntilock Brake System (ABS) on page 4-5for
more information.
Trailer Antilock Brake System
Warning Light
If your vehicle is connected
to a trailer with antilock
brakes, this light should
come on briefly, as a
check, when you turn on
the ignition.
When this light comes on and stays on, it means there
is something wrong in the trailer Antilock Brake
System (ABS). Have the system repaired immediately.
If an ABS equipped trailer is not connected, this
light is not functional.
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Page 155 of 384

Engine Coolant Temperature Gage
This gage shows the
engine coolant
temperature. If the gage
pointer moves into the
red area, your engine
coolant might have
overheated and your
engine may be too hot.
You should pull off the road, stop your vehicle and turn
off the engine as soon as possible.
SeeEngine Overheating on page 5-48. If you have a
Caterpillar
®diesel engine, also see your Caterpillar®
Operation & Maintenance Manual.
Low Coolant Warning Light
Your vehicle has a low
coolant warning light.
If this light comes on, the
system is low on coolant
and the engine may
overheat.
The warning light should come on briefly, as a check,
when you turn on the ignition.
When it comes on, you will also hear a warning tone for
10 seconds. SeeEngine Coolant (Caterpillar
®Diesel
Engines) on page 5-44orEngine Coolant (Gas and
DURAMAX
®/Isuzu 7.8L L6 Engines) on page 5-44
Engine Coolant and have your vehicle serviced as
soon as you can.
This light may also come on if your vehicle has the
automatic engine shutdown system and engine
shutdown has begun. SeeEngine Alarm and Automatic
Shutdown on page 2-18for more information.
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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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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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Low Washer Fluid Warning Light
This light is located above
the climate controls in the
center of the instrument
panel.
This light will come on when your vehicle is low on
windshield washer fluid.
For more information, seeWindshield Washer Fluid on
page 5-55.
Power Take-Off Light
For vehicles with Power
Take-Off (PTO), this light
is located in the center
of the instrument panel.
This light will come on when the PTO switch is in the
ON position. SeePower Take-Off (PTO) on page 2-32
for more information.
Check Gages Warning Light
This light will come on
briefly when the engine is
started.
If this light comes on and stays on while you are driving.
It means that either the engine coolant temperature
gage or the engine oil pressure gage may be showing a
reading in the warning zone.
When the check gages light comes on, you will also
hear a warning tone. The tone and the light will
stay activated until the problem is corrected.
This light may also come on if your vehicle is has
automatic engine shutdown system and engine
shutdown has begun. SeeEngine Alarm and Automatic
Shutdown on page 2-18.
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Water in Fuel Warning Light
This light is located above
the climate controls in the
center of the instrument
panel.
If your vehicle has the 6.6L DURAMAX
®or a
Caterpillar®diesel engine, this light will come on to
warn you that there is water in the fuel system.
For more information on how this light works, seeWater
in Fuel on page 5-12.
Change Fuel Filter Warning Light
For vehicles with this light,
it is located in the center of
the instrument panel.
If your vehicle has the DURAMAX
®6.6L engine, this
light will come on when the fuel filter needs to be
changed. If your vehicle has the Isuzu 6H 7.8L L6 diesel
engine, this light will come on when water is detected
in the fuel system and when the fuel filter needs to
be changed. SeeFuel Filter Replacement on page 5-18
andWater in Fuel on page 5-12for more information.
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Diesel Particulate Filter
Warning Light
Your vehicle may have
two Diesel Particulate
Filter (DPF) Warning lights.
These lights will come on briefly when the ignition is
turned to ON. One of these lights will come on
green during DPF regeneration. If the other light comes
on yellow, perform a manual regeneration or drive
the vehicle for automatic regeneration. If the light
changes from yellow to red, the DPF requires an
immediate regeneration. If the DPF is not regenerated,
the service engine soon light will come on and engine
power will be reduced.
SeeDiesel Particulate Filter (Diesel Engine) on
page 2-46andReduced Engine Power Light on
page 3-41for more information.
Air Filter Restriction Indicator
If your vehicle has this
feature, the gage is
located above the
switchbank in the center
of the instrument panel.
It monitors the engine
air filter.
As the filter gets dirty, the yellow indicator will begin to
rise. When it reaches the red/orange change area,
the filter should be replaced.
After replacing the filter, reset the gage by pressing in
the yellow reset button at the bottom of the gage.
If you have a Caterpillar
®diesel engine, also see your
Caterpillar®Operation & Maintenance Manual.
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