2003 CHEVROLET C/K warning light

2-74
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.
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 (Option)
When the key is turned to RUN or START, a tone will
sound for several seconds to remind people to fasten
their safety belts.

2-78 Charging System Indicator Light
The charging system
indicator 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 it
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
When your engine is
running, the voltmeter
gage, at the right side of
the instrument panel cluster,
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.

2-79 Service Transmission Warning Light
(If Equipped)
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. Using the transmission
shift control may result in the loss of 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 the service transmission warning light comes
on while you are driving, it is a warning that
making a transmission ªrangeº change could
leave you stranded. The vehicle may not continue
to move if you change gears with the
transmission shift control. The transmission can't
operate in all gears because something is wrong.
Leave the shift control alone and drive directly to
a GM dealer for service. If you can't go in for
service immediately, have the vehicle towed.

2-80 Range Inhibited Warning Indicator
(If Equipped)
If your vehicle is equipped with an Allison
1000/2000/2400 series automatic transmission, a lighted
bar under the current gear selected will flash.
If your vehicle is equipped with an Allison MD
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 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.
The BRAKE 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 ªHydraulic
Brake Systemsº in the Index.

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.