•If you have air brakes, the dual-needle air pressure
gage should read at least 115 psi (790 kPa) for
both service systems before you try to move
the vehicle. When air pressure is below 60 psi
(420 kPa), the LOW AIR light will come on and you
will hear a tone alarm. If the pressure doesn’t
build up or drops during warm-up, stop the engine
and find the cause before you try to move the
vehicle. Recommended air pressure before actually
driving away is 120 psi (830 kPa).
•The charging system light should come on when
the ignition key is turned to RUN or START and
should go out when the engine is running above
idle. If the light doesn’t go out or comes back
on during normal engine operation, have the
charging system checked right away. (This light
tells you if the generator is not charging; it doesn’t
reflect the condition of the battery.)
•The voltmeter charge indicator gage tells you the
condition of your battery’s charge. The gage
should be in the center area during engine
operation. The red area on the left indicates an
undercharge condition; the red area on the
right indicates an overcharge. If the gage is in
either red area, have the battery and charging
system checked right away.Notice:For diesel engines, don’t allow the engine
to operate at low idle for more than ve minutes.
This can cause low engine operating temperatures
which can affect engine operation and reduce
engine life. Engine idle speed should be increased
to 1200 rpm whenever extended idle is required.
Once started, the engine should be placed under
load to allow the engine coolant temperature
to reach 150°F (66°C) before shutting off the engine.
Engine Coolant Heater
If your vehicle has this
feature, the plug-in
receptacle is located under
the driver’s door.
In very cold weather, 0°F (−18°C) or colder, the engine
coolant heater can help. You’ll get easier starting
and better fuel economy during engine warm-up.
2-23
Your hazard warning
flashers 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 isn’t in.
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 won’t work. The hazard warning flashers will not
flash if the brakes are applied.Other Warning Devices
If you carry reflective triangles, you can set one up at
the side of the road behind your vehicle in the
recommended manner per Federal Motor Carrier Safety
Regulation (FMCSR) Section 392.22, to warn others.
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 the air brake system pressure drops below
60 psi (415 kPa).
3-6
Tachometer
This gage shows the engine speed in revolutions per
minute (rpm).
Safety Belt Reminder Light
When the key is turned to RUN or START, a light will
come on for several seconds to remind people to fasten
their safety belts.
The safety belt light will
also come on and stay on
for several seconds.
Safety Belt Reminder Tone
If your vehicle has this feature, when you turn your key
to RUN or START, a tone will sound for several
seconds to remind people to fasten their safety belts. 7.2L Caterpillar
®Diesel
Engine and 7.8L
DURAMAX™ Diesel
EnginesGasoline and 6.6L
DURAMAX™ Diesel
Engines
3-26
Air Bag Readiness Light
If your vehicle has air bags, there is an air bag readiness
light on the instrument panel, which shows the airbag
symbol. The system checks the air bag’s electrical
system for malfunctions. The light tells you if there is an
electrical problem. The system check includes the air
bag sensors, the air bag modules, the wiring, the
passenger air bag suppression circuit and the crash
sensing and diagnostic module. For more information on
the air bag system, seeAir Bag System on page 1-48.
This light will come on
when you start your
vehicle, and it will flash for
a few seconds. Then
the light should go out.
This means the system
is ready.
If the air bag readiness light stays on after you start the
vehicle or comes on when you are driving, your air
bag system may not work properly. Have your vehicle
serviced right away.The air bag readiness light should flash for a few
seconds when you turn the ignition key to RUN or
START. If the light doesn’t come on then, have it fixed
so it will be ready to warn you if there is a problem.
{CAUTION:
If the air bag readiness light stays on after you
start your vehicle, it means the air bag system
may not be working properly. The air bags in
your vehicle may not in ate in a crash, or they
could even in ate without a crash. To help
avoid injury to yourself or others, have your
vehicle serviced right away if the air bag
readiness light stays on after you start
your vehicle.
3-27
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 doesn’t
release fully.
This light should also come on when you turn the
ignition key to START. If it doesn’t come on then, have
it fixed so it will be ready to remind you if the parking
brake is applied or hasn’t released fully.
Anti-Lock Brake System
Warning Light
With the anti-lock brake
system, this light will come
on when you start your
engine and it may stay on
for several seconds.
That’s normal.
If the light stays on, or comes on when you’re driving,
your vehicle needs service. If the BRAKE or LOW
AIR warning light isn’t on, you still have brakes, but you
don’t have the anti-lock brake feature. If the BRAKE
and/or LOW AIR warning light is on, you don’t
have anti-lock brakes and there’s a problem with your
regular brakes. SeeBrake System Warning Light
on page 3-31.
The anti-lock brake system warning light should come
on briefly when you start the engine. If the light
doesn’t come on then, have it fixed so it will be ready to
warn you if there is a problem.
3-34
Low Coolant Warning Light
You have a low coolant
warning light. If this light
comes on, your 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 at
several beats per second for 10 seconds. SeeEngine
Coolant (Gas and DURAMAX™ engines) on page 5-32
orEngine Coolant (Caterpillar
®Diesel Engines) on
page 5-35and have your vehicle serviced as soon as
you can.
This light may also come on if your vehicle is equipped
with the automatic engine shutdown system and
engine shutdown has begun. SeeEngine Alarm and
Automatic ShutdownunderStarting Your Diesel Engine
on page 2-14.
Wait to Start Indicator
If your vehicle has the DURAMAX™ 6600, you will have
glow plugs. If your vehicle has the DURAMAX™ 7800,
you will have glow plugs and an inlet heater. If your
vehicle has a Caterpillar
®engine, you will have an inlet
heater.
The light in the center of
the instrument panel will
come on when the
inlet heater is on and the
ignition key is in RUN.
Wait until the indicator light turns off before turning the
ignition key to START.
3-36
Many adults — by some estimates, nearly half the adult
population — choose never to drink alcohol, so they
never drive after drinking. For persons under 21,
it is against the law in every U.S. state to drink alcohol.
There are good medical, psychological and
developmental reasons for these laws.
The obvious way to eliminate the leading highway
safety problem is for people never to drink alcohol and
then drive. But what if people do? How much is “too
much” if someone plans to drive? It is a lot less
than many might think. Although it depends on each
person and situation, here is some general information
on the problem.
The Blood Alcohol Concentration (BAC) of someone
who is drinking depends upon four things:
•The amount of alcohol consumed
•The drinker’s body weight
•The amount of food that is consumed before and
during drinking
•The length of time it has taken the drinker to
consume the alcohol.
According to the American Medical Association, a 180 lb
(82 kg) person who drinks three 12 ounce (355 ml)
bottles of beer in an hour will end up with a BAC
of about 0.06 percent. The person would reach thesame BAC by drinking three 4 ounce (120 ml) glasses
of wine or three mixed drinks if each had 1-1/2 ounces
(45 ml) of liquors like whiskey, gin or vodka.
It is the amount of alcohol that counts. For example, if
the same person drank three double martinis (3 ounces
or 90 ml of liquor each) within an hour, the person’s
BAC would be close to 0.12 percent. A person
who consumes food just before or during drinking will
have a somewhat lower BAC level.
4-3