trailer CHEVROLET C/K 2003 User Guide

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.

4-11
Steering
Power Steering
If you lose power steering assist because the engine
stops or the system is not functioning, you can steer
but it will take much more effort.
On vehicles with hydraulic brakes, the power steering
and main hydraulic brake system both use the power
steering pump. See ªHydraulic Brake Systemsº in
the Index.
Steering Tips
Driving on Curves
It's important to take curves at a reasonable speed.
A lot of the ªdriver lost controlº accidents mentioned
on the news happen on curves. Here's why:
Experienced driver or beginner, each of us is subject to
the same laws of physics when driving on curves. The
traction of the tires against the road surface makes it
possible for the vehicle to change its path when you turn
the front wheels. If there's no traction, inertia will keep
the vehicle going in the same direction. If you've ever
tried to steer a vehicle on wet ice, you'll understand this.The traction you can get in a curve depends on the
condition of your tires and the road surface, the angle at
which the curve is banked, and your speed. While you're
in a curve, speed is the one factor you can control.
Suppose you're steering through a sharp curve. Then you
suddenly accelerate. Both control systems
-- steering and
acceleration
-- have to do their work where the tires meet
the road. Adding the sudden acceleration can demand too
much of those places. You can lose control. Refer to
ªTraction Control Systemº in the Index.
What should you do if this ever happens? Ease up on the
brake or accelerator pedal, steer the vehicle the way you
want it to go, and slow down.
Speed limit signs near curves warn that you should
adjust your speed. Of course, the posted speeds are
based on good weather and road conditions. Under less
favorable conditions you'll want to go slower.
If you need to reduce your speed as you approach a
curve, do it before you enter the curve, while your front
wheels are straight ahead.
This is especially important with a tractor
-trailer. Try to
adjust your speed so you can ªdriveº through the curve.
Maintain a reasonable, steady speed. Wait to accelerate
until you are out of the curve, and then accelerate gently
into the straightaway.

4-12 Steering in Emergencies
There are times when steering can be more effective
than braking. For example, you come over a hill and
find a truck stopped in your lane, or a car suddenly pulls
out from nowhere, or a child darts out from between
parked cars and stops right in front of you. You can
avoid these problems by braking
-- if you can stop
in time. But sometimes you can't; there isn't room.
That's the time for evasive action
-- steering around
the problem.
In emergencies like these, first apply your brakes. See
ªBraking in Emergenciesº earlier in this section. It is
better to remove as much speed as you can from a
possible collision. Then steer around the problem, to the
left or right depending on the space available. Since
your vehicle has anti
-lock brakes, you don't need to
release the brakes to maintain steering control.
An emergency like this requires close attention and a
quick decision. If you are holding the steering wheel at
the recommended 9 and 3 o'clock positions, you may be
able to turn it just enough to miss the object without
removing either hand. But you must act fast, steering
precisely. The more sharply you turn, the greater the
chance of a skid, a rollover or a ªjackknifeº with a
tractor
-trailer. Just as quickly straighten the wheel once
you have avoided the object.
The fact that such emergency situations are always
possible is a good reason to practice defensive driving at
all times and wear safety belts properly.

5-26
Engine Fan Noise
Your vehicle has a clutched engine cooling fan. When
the clutch is engaged, the fan spins faster to provide
more air to cool the engine. In most everyday driving
conditions, the clutch is not fully engaged. This
improves fuel economy and reduces fan noise. Under
heavy vehicle loading, trailer towing and/or high outside
temperatures, the fan speed increases when the clutch
engages. So you may hear an increase in fan noise.
This is normal and should not be mistaken as the
transmission slipping or making extra shifts. It is merely
the cooling system functioning properly. The fan will
slow down when additional cooling is not required and
the clutch disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch disengages.
If a Tire Goes Flat
It's unusual for a tire to ªblow outº while you're driving,
especially if you maintain your tires properly. If air goes
out of a tire, it's much more likely to leak out slowly.
But if you should ever have a ªblowout,º here are a few
tips about what to expect and what to do:
If a front tire fails, the flat tire will create a drag that
pulls the vehicle toward that side. Take your foot off the
accelerator pedal and grip the steering wheel firmly.
Steer to maintain lane position, and then gently brake to
a stop well out of the traffic lane.
A rear blowout, particularly on a curve, acts much like a
skid and may require the same correction you'd use in a
skid. In any rear blowout, remove your foot from the
accelerator pedal. Get the vehicle under control by
steering the way you want the vehicle to go. It may be
very bumpy and noisy, but you can still steer. Gently
brake to a stop
-- well off the road if possible.
If a tire goes flat, avoid further tire and wheel damage
by driving slowly to a level place and turn on your
hazard warning flashers. The next part tells you what
to do.

6-76
Vehicle Identification Number (VIN)
This is the legal identifier for your vehicle. It appears on
a plate in the front corner of the instrument panel, on the
driver's side. You can see it if you look through the
windshield from outside your vehicle. The VIN also
appears on the Vehicle Certification and Service Parts
labels and the certificates of title and registration.
Engine Identification
The 8th character in your VIN is the engine code. This
code will help you identify your engine, specifications
and replacement parts.
Service Statement
One of these statements is on your GVW Rating label.
Here is what each one means.
TRUCK SERVICE
-- A vehicle made to carry
property or special equipment. It is made for uniform
frame loading. That includes using the vehicle to pull a
full trailer.
TRUCK
-TRACTOR -- A vehicle made to draw other
vehicles. It's made to carry part of the load of the trailer.
It is made for point frame loading, usually for a
semi
-trailer (ªfifth wheelº).
MAX. VERT. CG
-- The highest allowable vertical
center of gravity, at the highest allowable GVWR. It's
measured from level ground in inches.
TRUCK
-CANADA -- A vehicle first sold in Canada
with a non
-school bus application, or cab models with
regular production option RQ2 (ªtruck serviceº).
TRACTOR
-CANADA -- A cab model with regular
production option RQ3 (ªtruck
-tractor serviceº).

6-81
Fuse Usage
RH PARK LP Right
-hand Parking Lamps
LH PARK LP Left
-hand Parking Lamps
RADIO U Radio
PWR WINDOW Power Windows
BRAKE ISO Brake Warning Lamp
SPARE Spare Fuse
L
-RR TRUCK Left Rear Trailer Wiring
SPARE Spare Fuse
SPARE Spare Fuse
SPARE Spare Fuse
R
-RR TRUCK Right Rear Trailer Wiring
SPARE Spare FuseRelay Usage
BRAKE LAMP C4/C5 Brake Lamps, C6/C7/C8
Tractor/Trailer Wiring
IGN 4 Ignition
MARKER LP Sidemarker and Clearance Lamps
HTD FUEL LB7/LG4 Heated Fuel
AIR HTR LG4 Air Heater
ECU
MAINTAINLG4 Electronic Control Unit
DRL Daytime Running Lamps
CHMSL ISO Center High Mounted Stop Lamp
HTD MIRR Heated Mirrors
R-TRN TLR Right Trailer Turn Signal
L
-TRN TLR Left Trailer Turn Signal
SPARE Spare Relay
SPARE Spare Relay
SPARE Spare Relay

6-82
Fuse Block 2
Circuit Breaker Usage
1 Stoplamps
2 Center High Mounted Stop Lamp
3 Parking Lamps
4 Powertrain Control Module
5 Auxiliary Wiring
6 Heater/Air ConditioningCircuit Breaker Usage
7 Hazard Warning Flashers
8 Power Post
9 Courtesy Lamps
10 Warning Lights, Gages
and Indicators
11 Crank
12 Rear Axle
13 Trailer Turn Signals/Hazard
Warning Flashers
14 Radio/Chime
15 Daytime Running Lamps
16 Air Bag System
17 Exterior/Interior Lamps
18 Parking Brake
19 Accessory Power
20 Ignition
21 Sidemarker Lamps
22 Turn Signal/Backup Lamps
23 Transmission
24 Chassis
A Spare
B Spare

7-7
Wheel bearing (grease type) service (or every
24 months, whichever occurs first, and whenever
hubs are removed). (23)(46)
Wheels and tires service. (15)
Parking brake service (or every 6 months, whichever
occurs first). (8)
Air intake system service (or every 24 months,
whichever occurs first). (4)(5)(24)
Evaporative Control System service (if equipped) (or
every 24 months, whichever occurs first). (3)(26)

Rear axle air shift motor service. (11)
Air brake service (or every 6 months, whichever
occurs first). (39)
Air brake automatic slack adjuster service
(or every 500 hours, whichever occurs first). (40)
Check air brake relay valve operation and check
for leaks (or every month, or every 300 hours,
whichever occurs first).
Clean air brake application valve (or every 3 months,
or every 300 hours, whichever occurs first); lubricate
linkage.
Air brake chamber service (or every 2 months,
whichever occurs first). (41)Trailer brake hand control valve service (or every
3 months, or every 900 hours, whichever
occurs first). (42)
L18/LB7 Engines Only: Clutch pedal free
travel service. (10)
30,000 Miles (48 000 km)
Gasoline Engine Only: Check Oil Life System.
If engine oil and filter are changed, reset system.
See ªEngine Oilº in the Index. (3)(9)
DURAMAX Diesel Only: Change engine oil
and filter (or every 12 months, whichever occurs
first). (2)(3)
Check fluid levels (or every 3 months, whichever
occurs first). (1)(6)
DURAMAX Diesel Only: Replace fuel filter.
Chassis lubrication service (or every 6 months,
whichever occurs first). (12)
Replace fuel filter(s) (or every 12 months, whichever
occurs first). (3)
Steering system service. (13)
Front and rear suspension service. (14)
Spring
-to-axle U-bolts and shackle bolts
service. (16)
Exhaust system service (or every 6 months,
whichever occurs first). (3)(4)(17)
(Continued)

7-9
Wheel bearing (grease type) service (or every
24 months, whichever occurs first, and whenever
hubs are removed). (23)(46)
Inspect door hinge pins and bushings and replace
as necessary.
Steering system service. (13)
Front and rear suspension service. (14)
Spring
-to-axle U-bolts and shackle
bolts service. (16)
Exhaust system service (or every 6 months,
whichever occurs first). (3)(4)(17)
Wheels and tires service. (15)
Hydraulic brake service (or every 6 months,
whichever occurs first). (7)(46)
Parking brake service (or every 6 months, whichever
occurs first). (8)
Thermostatically controlled engine cooling fan
service. (4)(20)
Shields and underhood insulation service. (4)(5)(21)
Rear axle air shift motor service. (11)
Air intake system service (or every 24 months,
whichever occurs first). (4)(5)(24)
Evaporative Control System service (if equipped) (or
every 24 months, whichever occurs first). (3)(26)
Air brake service (or every 6 months, whichever
occurs first). (39)
Air brake automatic slack adjuster service
(or every 500 hours, whichever occurs first). (40)
Check air brake relay valve operation and check for
leaks (or every month, or every 300 hours,
whichever occurs first).
Clean air brake application valve (or every 3 months,
or every 300 hours, whichever occurs first); lubricate
linkage.
Air brake chamber service (or every 2 months,
whichever occurs first). (41)
Trailer brake hand control valve service (or every
3 months, or every 900 hours, whichever
occurs first). (42)
L18/LB7 Engines Only: Clutch pedal free
travel service. (10)
50,000 Miles (80 000 km)
DURAMAX Diesel Only: Change engine oil
and filter (or every 12 months, whichever occurs
first). (2)(3)
Inspect air compressor discharge port (or every
6 months or every 1,800 hours, whichever
occurs first).

7-11
67,500 Miles (108 000 km)
Gasoline Engine Only: Check Oil Life System.
If engine oil and filter are changed, reset system.
See ªEngine Oilº in the Index. (3)(9)
Check fluid levels (or every 3 months, whichever
occurs first). (1)(6)
Chassis lubrication service (or every 6 months,
whichever occurs first). (12)
Cooling system service. Clean the cooling system
filler cap with clean water, clean the core, pressure
test the cap and the system for proper pressure
capability and inspect condition of cooling and
heater hoses and clamps. Replace hoses if cracked,
swollen or damaged.
Wheel bearing (grease type) service (or every
24 months, whichever occurs first, and whenever
hubs are removed). (23)(46)
Wheels and tires service. (15)
Parking brake service (or every 6 months, whichever
occurs first). (8)
Rear axle air shift motor service. (11)
Air intake system service (or every 24 months,
whichever occurs first). (4)(5)(24)Evaporative Control System service (if equipped) (or
every 24 months, whichever occurs first). (3)(26)

Air brake service (or every 6 months, whichever
occurs first). (39)
Air brake automatic slack adjuster service (or every
500 hours, whichever occurs first). (40)
Check air brake relay valve operation and check
for leaks (or every month, or every 300 hours,
whichever occurs first).
Clean air brake application valve (or every 3 months,
or every 300 hours, whichever occurs first); lubricate
linkage.
Air brake chamber service (or every 2 months,
whichever occurs first). (41)
Trailer brake hand control valve service
(or every 3 months, or every 900 hours,
whichever occurs first). (42)
L18/LB7 Engines Only: Clutch pedal free
travel service. (10)
70,000 Miles (112 000 km)
DURAMAX Diesel Only: Change engine
oil and filter (or every 12 months, whichever
occurs first). (2)(3)