brake light CHEVROLET C/K 2003 Owner's Manual

2-81
If the amber SERVICE
BRAKES SOON warning
light comes on, it means
that there is something
wrong in the brake system.
When this light comes on, you will also hear a warning
tone. If this light comes on, have the system repaired
immediately.
Both of these lights should come on briefly every time
you start the 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 and stay 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. See ªTowing Your Vehicleº in the Index. See
ªHydraulic Brake Systemsº in the Index for more
information.
CAUTION:
Your brake system may not be working properly
if a brake system warning light is on. Driving
with a brake system warning light on can lead to
an accident. If the light is still on after you've
pulled off the road and stopped carefully, have
the vehicle towed for service.

2-82
Air Brake System Warning Light
Vehicles with air brake systems have one brake system
warning light on the instrument panel.
United States Canada
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 this warning light comes on, you will also hear a
warning tone. If the warning light and tone come on
while you are driving, you should drive only as far as
the nearest point of safety and then stop the vehicle.
Here's a very important thing for you to know:
CAUTION:
If the LOW AIR 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 LOW AIR
warning light comes on and the warning tone
sounds, stop as soon as you can. You won't know
how quickly the system is losing pressure, so be
aware that the parking brake may come on
suddenly.

2-83 Parking Brake Indicator Light
Your vehicle has a brake
indicator 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. See ªBrake System Warning Lightº earlier in
this section.
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.

2-84 Trailer Anti-Lock Brake System
Warning Light
If your vehicle is connected
to an anti
-lock brake system
equipped trailer, 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 anti
-lock brake system.
Have the system repaired immediately.
If an anti
-lock brake system equipped trailer is not
connected, this light is not functional.
Engine Coolant Temperature Gage
United States Canada
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.
See ªEngine Overheatingº in the Index. If you have a
Caterpillar

diesel engine, also see your Caterpillar

Operation & Maintenance Manual.

2-91 Exhaust Brake Indicator Light
(If Equipped)
If your vehicle is equipped
with an exhaust brake, you
will have this light, located
above the comfort controls
in the center of the
instrument panel.
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, see ªDiesel
Engine Exhaust Brakeº in the Index.
Diff Lock Indicator Light (If Equipped)
This light located in the
center of the instrument
panel is on when the
inter
-axle 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.

2-94 Air Pressure Gage (If Equipped)
If your vehicle has air
brakes, the air pressure gage
is located above the
switchbank in the center of
the instrument panel.
This gage shows the air pressure for both your front and
rear brake systems.
If the needle on the gage indicates that the air pressure is
below 60 to 75 psi (415 to 517 kPa), the low air warning
light will come on. An alarm will also sound if this
happens.
The yellow pointer shows the pressure available for the
front system, while the green pointer shows pressure for
the rear. There should be no more than 4 psi (28 kPa)
difference showing between the systems.
Don't drive until both pointers are showing at least
115 psi (793 kPa), so you'll have enough air if you
need to apply your brakes.
Air Filter Restriction Indicator (Option)
This optional 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 25 inches of vacuum on the scale,
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 diesel engine, also see your Caterpillar


Operation & Maintenance Manual.

4-7
Avoid needless heavy braking. Some people drive in
spurts
-- heavy acceleration followed by heavy
braking
-- rather than keeping pace with traffic. This is a
mistake. Your brakes may not have time to cool between
hard stops. Your brakes will wear out much faster if you
do a lot of heavy braking. If you keep pace with the
traffic and allow realistic following distances, you will
eliminate a lot of unnecessary braking. That means
better braking and longer brake life.
If your engine ever stops while you're driving, brake
normally but don't pump your brakes. If you do, the
pedal may get harder to push down. If your engine
stops, you will still have some power brake assist. But
you will use it when you brake. Once the power assist is
used up, it may take longer to stop and the brake pedal
will be harder to push.
Hydraulic Brake Systems
If your engine stops running, or if your primary brake
system stops working, your vehicle has a reserve power
assist system to help you slow down. Just slowly and
steadily apply the brake pedal until you can safely get
off the road. The pedal will seem harder to push down.
Don't pump the pedal; the system won't work well or at
all that way.
You may find that the steering wheel seems hard to turn
when you're turning and braking at the same time. Also,
the PRIMARY BRAKE warning light may come on and
the warning tone may sound. This is normal because the
main hydraulic brake system and power steering both
use the power steering pump. If this ever happens, let up
on the brake pedal a little. When you let up on the brake
pedal in that situation, it lets the steering get a little
more help from the pump.

4-8 Anti-Lock Brake System (ABS)
Your vehicle has anti-lock brakes. ABS is an advanced
electronic braking system that will help prevent a
braking skid.
When you start your engine and begin to drive away,
your anti
-lock brake system will check itself. You may
hear a momentary motor or clicking noise while this test
is going on. This is normal.
If there's a problem with the
anti
-lock brake system, this
warning light will stay on.
See ªAnti
-Lock Brake
System Warning Lightº in
the Index.
Let's say the road is wet and you're driving safely.
Suddenly, an animal jumps out in front of you. You slam
on the brakes and continue braking. Here's what
happens with ABS:
A computer senses that wheels are slowing down. If one
of the wheels is about to stop rolling, the computer will
separately work the brakes at each wheel.

4-10
Traction Control System (TCS)
(Option)
Your vehicle may have a traction control system that
limits wheel spin. This is especially useful in slippery
road conditions. The system operates only if it senses
that one or both of the rear wheels are spinning or
beginning to lose traction. When this happens, the
system applies the brake(s) at the affected wheel(s).
The bottom light on the TCS on/off button will come on
when the TCS is limiting wheel spin. You may feel or
hear the system working, but this is normal. The TCS
will function at speeds up to about 25 mph (42 km/h).
The TCS may operate on dry roads under some
conditions. When this happens, you may notice a
reduction in acceleration. This is normal and doesn't
mean there's a problem with your vehicle. Examples of
these conditions include a hard acceleration in a turn, an
abrupt upshift or downshift of the transmission or
driving on rough roads.
When the light in the top of the TCS button is on, the
TCS is off and will not limit wheel spin. Adjust your
driving accordingly.
The light in the top of the TCS button will come on if
the TCS is turned off by pressing the TCS on/off button.The light may also come on if a problem has been
detected in either the traction control system or the
anti
-lock brake system.
The traction control system automatically comes on
whenever you start your vehicle. To limit wheel spin,
especially in slippery road conditions, you should
always leave the system on. But you can turn the
traction control system off if you ever need to. You
should turn the system off if your vehicle ever gets stuck
in sand, mud or snow and rocking the vehicle is
required. See ªRocking Your Vehicleº in the Index.
To turn the system on
or off, press the traction
control button located in
the instrument panel
switchbank.
If you used the TCS button to turn the system off, the
light in the top of the button will come on and stay on.
You can turn the TCS back on at any time by pressing
the button again; the light should go off.

4-19
Driving too fast through large water puddles or even
going through some vehicle washes can cause problems,
too. The water may affect your brakes. Try to avoid
puddles. But if you can't, try to slow down before you
hit them.
CAUTION:
Wet brakes can cause accidents. They won't work
as well in a quick stop and may cause pulling to
one side. You could lose control of the vehicle.
After driving through a large puddle of water or
a vehicle wash, apply your brake pedal lightly
until your brakes work normally.
Hydroplaning
Hydroplaning is dangerous. So much water can build up
under your tires that they can actually ride on the water.
This can happen if the road is wet enough and you're
going fast enough. When your vehicle is hydroplaning,
it has little or no contact with the road.
Hydroplaning doesn't happen often. But it can if your
tires do not have much tread or if the pressure in one or
more is low. It can happen if a lot of water is standing on
the road. If you can see reflections from trees, telephone
poles or other vehicles, and raindrops ªdimpleº the
water's surface, there could be hydroplaning.
Hydroplaning usually happens at higher speeds. There
just isn't a hard and fast rule about hydroplaning. The
best advice is to slow down when it is raining.