wiring CHEVROLET EXPRESS 2003 Owners Manual

;(Parking Lamps):Turn the control to this
position to turn on the parking lamps, together with
the following:
Instrument Panel Lights
Daytime Running Lamps (DRL) (Canada)
Sidemarker Lamps
Taillamps
License Plate Lamps
If the DRL are active when the control is turned to this
position, the DRL will turn off.
For vehicles rst sold in Canada, the DRL will remain
active along with the lamps mentioned above.
5(Headlamps):Turn the control to this position to
turn on the headlamps together with the parking
lamps and turn off the daytime running lamps.
You can switch your headlamps from high to low-beam
by pulling the turn signal/high-beam lever toward you.
A circuit breaker protects your headlamps. If you have
an electrical overload, your headlamps will icker on
and off. Have your headlamp wiring checked right away
if this happens.
Headlamps on Reminder
A reminder chime will sound when your control is turned
to the headlamps or parking lamps position, your key
is out of the ignition, and your driver’s door is open. To
disable the chime, turn the control to the Daytime
Running Lamp (DRL) position and then back to the
parking lamps or headlamps position.
Daytime Running Lamps (DRL)
Daytime Running Lamps (DRL) can make it easier for
others to see the front of your vehicle during the
day. DRL can be helpful in many different driving
conditions, but they can be especially helpful in the short
periods after dawn and before sunset. Fully functional
daytime running lamps are required on all vehicles
rst sold in Canada.
The DRL system will come on when the following
conditions are met:
the ignition is on,
the exterior lamps control is in DRL mode and not
in the defeat position.
When the DRL are on, only your headlamps will be on.
The taillamps, sidemarker and other lamps won’t be
on. The instrument panel will be lit.
3-14

Safety Belt Reminder Light
When the key is turned to RUN or START, a chime will
be provided for several seconds to remind people to
buckle their safety belts. The driver safety belt light will
also be provided and stay on for several seconds,
then it will ash for several more. You should buckle
your seat belt.
This chime and light will be
repeated if the driver
remains unbuckled and the
vehicle is in motion.
If the driver’s belt is buckled, neither the chime nor the
light will be provided.
Airbag Readiness Light
There is an airbag readiness light on the instrument
panel, which shows the airbag symbol. The system
checks the airbag’s electrical system for malfunctions.
The light tells you if there is an electrical problem.
The system check includes the airbag sensor, the airbag
modules, the wiring and the crash sensing and
diagnostic module. For more information on the airbag
system, seeAirbag System on page 1-59.
This light will come on
when you start your
vehicle, and it will ash for
a few seconds. Then
the light should go out.
This means the system
is ready.
3-25

If you’ll be pulling a trailer that, when loaded, will weigh
more than 5,000 lbs (2 270 kg), be sure to use a
properly mounted weight-distributing hitch and sway
control of the proper size. This equipment is very
important for proper vehicle loading and good handling
when you’re driving. You should always use a sway
control if your trailer will weigh more than these limits.
You can ask a hitch dealer about sway controls.
Will you have to make any holes in the body of your
vehicle when you install a trailer hitch?
If you’re using the wiring provided with the
factory-installed trailering package, you should not need
to make any holes in the body of your vehicle.
However, if you have an aftermarket hitch installed, you
may need to make holes in the body.
If you do, then be sure to seal the holes later when you
remove the hitch. If you don’t seal them, deadly
carbon monoxide (CO) from your exhaust can get into
your vehicle as well as dirt and water. See “Carbon
Monoxide” underEngine Exhaust on page 2-27.Safety Chains
You should always attach chains between your vehicle
and your trailer. Cross the safety chains under the
tongue of the trailer to help prevent the tongue from
contacting the road if it becomes separated from
the hitch. Instructions about safety chains may be
provided by the hitch manufacturer or by the trailer
manufacturer. Follow the manufacturer’s
recommendation for attaching safety chains and do not
attach them to the bumper. Always leave just enough
slack so you can turn with your rig. Never allow
safety chains to drag on the ground.
Trailer Brakes
If your trailer weighs more than 1,000 lbs (450 kg)
loaded, then it needs its own brakes – and they must be
adequate. Be sure to read and follow the instructions
for the trailer brakes so you’ll be able to install,
adjust and maintain them properly.
Since your vehicle is equipped with StabiliTrak, your
trailer brake system cannot tap into the vehicle’s
hydraulic brake system.
4-42

Passing
You’ll need more passing distance up ahead when
you’re towing a trailer. And, because you’re a good deal
longer, you’ll need to go much farther beyond the
passed vehicle before you can return to your lane.
Backing Up
Hold the bottom of the steering wheel with one hand.
Then, to move the trailer to the left, just move that hand
to the left. To move the trailer to the right, move your
hand to the right. Always back up slowly and, if possible,
have someone guide you.
Making Turns
Notice:Making very sharp turns while trailering
could cause the trailer to come in contact with the
vehicle. Your vehicle could be damaged. Avoid
making very sharp turns while trailering.
When you’re turning with a trailer, make wider turns than
normal. Do this so your trailer won’t strike soft shoulders,
curbs, road signs, trees or other objects. Avoid jerky or
sudden maneuvers. Signal well in advance.
Turn Signals When Towing a Trailer
When you tow a trailer, your vehicle has to have extra
wiring and a heavy-duty turn signal asher (included
in the optional trailering package).
The arrows on your instrument panel will ash whenever
you signal a turn or lane change. Properly hooked up,
the trailer lamps will also ash, telling other drivers
you’re about to turn, change lanes or stop.
When towing a trailer, the arrows on your instrument
panel will ash for turns even if the bulbs on the trailer
are burned out. Thus, you may think drivers behind
you are seeing your signal when they are not. It’s
important to check occasionally to be sure the trailer
bulbs are still working.
4-44

When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:
start your engine,
shift into a gear, and
release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store
the chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you’re
pulling a trailer. See the Maintenance Schedule for more
on this. Things that are especially important in trailer
operation are automatic transmission uid (don’t overll),
engine oil, axle lubricant, belt, cooling system and
brake system. Each of these is covered in this manual,
and the Index will help you nd them quickly. If
you’re trailering, it’s a good idea to review these sections
before you start your trip.
Check periodically to see that all hitch nuts and bolts
are tight.
Trailer Wiring Harness
The optional heavy-duty trailer wiring package includes
a seven-wire harness assembly at the rear of the
vehicle and a four-wire harness assembly under the left
hand side of the instrument panel. The seven-wire
harness assembly is taped together and located in a
frame pocket at the driver side rear left corner of
the frame. The seven-wire harness includes a 30-amp
feed wire. Both harnesses come without connectors and
should be wired by a qualied electrical technician.
The technician can use the following color code chart
when connecting the wiring harness to your trailer
and trailer brake controller.
Seven-Wire Harness
Light Green: Back-up lamps
Brown: Parking lamps
Yellow: Left stoplamp and turn signal
Dark Green: Right stoplamp and turn signal
Dark Blue: Use for electric trailer brakes
Orange: Trailer accessory
White (heavy gage): Ground wire
Four-Wire Harness (Trailer Brake Controller)
Black: Ground
Red/White Stripe: Fused Battery
Dark Blue: Trailer Brake Feed
Light Blue: Fused Stoplamp/CHMSL
4-46

Buying New Tires.........................................5-62
Uniform Tire Quality Grading..........................5-63
Wheel Alignment and Tire Balance..................5-64
Wheel Replacement......................................5-65
Tire Chains..................................................5-66
If a Tire Goes Flat........................................5-67
Changing a Flat Tire.....................................5-68
Removing the Spare Tire and Tools................5-69
Removing the Flat Tire and Installing the
Spare Tire................................................5-72
Secondary Latch System...............................5-77
Storing a Flat or Spare Tire and Tools............5-80
Spare Tire...................................................5-82
Appearance Care............................................5-82
Fabric/Carpet...............................................5-83
Vinyl...........................................................5-85
Instrument Panel..........................................5-85
Interior Plastic Components............................5-85
Glass Surfaces.............................................5-85
Care of Safety Belts......................................5-85
Weatherstrips...............................................5-86
Washing Your Vehicle...................................5-86Cleaning Exterior Lamps/Lenses.....................5-86
Finish Care..................................................5-86
Windshield and Wiper Blades.........................5-87
Aluminum Wheels.........................................5-88
Tires...........................................................5-88
Sheet Metal Damage.....................................5-89
Finish Damage.............................................5-89
Underbody Maintenance................................5-89
Chemical Paint Spotting.................................5-89
Vehicle Care/Appearance Materials..................5-90
Vehicle Identication......................................5-91
Vehicle Identication Number (VIN).................5-91
Service Parts Identication Label.....................5-91
Electrical System............................................5-92
Add-On Electrical Equipment..........................5-92
Headlamp Wiring..........................................5-92
Windshield Wiper Fuses................................5-92
Fuses and Circuit Breakers............................5-92
Floor Console Fuse Block..............................5-93
Engine Compartment Fuse Block....................5-94
Capacities and Specications..........................5-97
Section 5 Service and Appearance Care
5-2

Electrical System
Add-On Electrical Equipment
Notice:Don’t add anything electrical to your
vehicle unless you check with your dealer rst.
Some electrical equipment can damage your vehicle
and the damage wouldn’t be covered by your
warranty. Some add-on electrical equipment
can keep other components from working as
they should.
Your vehicle has an air bag system. Before attempting
to add anything electrical to your vehicle, see
Servicing Your Airbag-Equipped Vehicle on page 1-69.
Headlamp Wiring
The headlamp wiring is protected by a circuit breaker in
the lamp switch. An electrical overload will cause the
lamps to icker on and off, or in some cases to remain
off. If this happens, have your headlamp wiring
checked right away.
Windshield Wiper Fuses
The windshield wiper motor is protected by a circuit
breaker and a fuse. If the motor overheats due to heavy
snow, etc., the wiper will stop until the motor cools.
Although the circuit is protected from electrical overload,
overload due to heavy snow, etc., may cause wiper
linkage damage. Always clear ice and heavy snow from
the windshield before using the windshield wipers. If
the overload is caused by some electrical problem and
not snow, etc., be sure to get it xed.
Fuses and Circuit Breakers
The wiring circuits in your vehicle are protected from
short circuits by a combination of fuses and circuit
breakers. This greatly reduces the chance of res
caused by electrical problems.
Look at the silver-colored band inside the fuse. If the
band is broken or melted, replace the fuse. Be sure you
replace a bad fuse with a new one of the identical
size and rating.
5-92

Fuse Usage
21 Trailer Park Lamp
22 Front Park Lamp
32 Auxilary 1
33 Auxilary 2
Relays Usage
23 Window Residual Accessory Power
24 Auxiliary
25 Right Rear Defogger
26 Courtesy Lamp
27 Cargo Unlock
28 Driver Unlock
29 Park Lamp
30 Door Locks
31 Passenger Unlock
Circuit Breaker Usage
34 Power Window
Engine Compartment Fuse Block
The fuse block is located in the engine compartment on
the driver’s side of the vehicle.
Fuse Usage
1 Radio Battery
2 Powertrain Control Module Battery
3 Left Rear Turn Lamp
4 Right Rear Turn Lamp
5 Back-up Lamps Trailer Wiring
5-94

D
Daytime Running Lamps..................................3-14
Daytime Running Lamps Indicator Light.............3-37
Defensive Driving............................................. 4-2
Doing Your Own Service Work........................... 5-4
Dome Lamp Override......................................3-15
Dome Lamps.................................................3-15
Door
60/40 Swing-Out Side Door...........................2-12
Cargo Door Relocking.................................... 2-8
Locks.......................................................... 2-7
Power Door Locks......................................... 2-8
Rear Door Security Locks............................... 2-8
Rear Doors.................................................2-13
Sliding Side Door........................................2-10
Driver
Position, Safety Belt.....................................1-15
Driving
At Night.....................................................4-15
City...........................................................4-19
Defensive..................................................... 4-2
Drunken....................................................... 4-2
Freeway.....................................................4-20
Hill and Mountain Roads..............................4-22
In Rain and on Wet Roads...........................4-16
Rocking Your Vehicle to Get it Out.................4-28
Winter........................................................4-24
Dual Tire Operation.........................................5-59
E
Electrical System
Add-On Equipment......................................5-92
Engine Compartment Fuse Block...................5-94
Floor Console Fuse Block.............................5-93
Fuses and Circuit Breakers...........................5-92
Headlamp Wiring.........................................5-92
Windshield Wiper Fuses...............................5-92
Engine
Air Cleaner/Filter.........................................5-17
Battery.......................................................5-37
Change Engine Oil Light...............................3-35
Check and Service Engine Soon Light............3-32
Coolant......................................................5-22
Coolant Heater............................................2-21
Coolant Temperature Gage...........................3-31
Engine Compartment Overview......................5-12
Exhaust.....................................................2-27
Fan Noise..................................................5-32
Fuel Regulator............................................2-20
Oil .............................................................5-13
Overheating................................................5-24
Reduced Power Light...................................3-37
Speed Limiter.............................................3-24
Starting......................................................2-20
Entry Lighting.................................................3-16
Event Data Recorders (EDR)............................. 7-9
Exit Lighting...................................................3-16
4

Extender, Safety Belt.......................................1-30
Exterior Lamps...............................................3-13
F
Filter
Engine Air Cleaner......................................5-17
Finish Damage...............................................5-89
Fixed Mast Antenna........................................3-74
Flash-to-Pass................................................... 3-9
Flat Tire........................................................5-67
Flat Tire, Changing.........................................5-68
Flat Tire, Storing.............................................5-80
Fluid
Automatic Transmission................................5-19
Power Steering...........................................5-32
Windshield Washer......................................5-33
Front Axle......................................................5-44
Fuel............................................................... 5-5
Additives...................................................... 5-6
California Fuel.............................................. 5-6
Filling a Portable Fuel Container....................5-10
Filling Your Tank........................................... 5-8
Fuels in Foreign Countries.............................. 5-7
Gage.........................................................3-38
Gasoline Octane........................................... 5-5
Gasoline Specications.................................. 5-5
Regulator...................................................2-20Fuses
Engine Compartment Fuse Block...................5-94
Floor Console Fuse Block.............................5-93
Fuses and Circuit Breakers...........................5-92
Windshield Wiper.........................................5-92
G
Gage
Check Gages Warning Light..........................3-38
Engine Coolant Temperature.........................3-31
Fuel..........................................................3-38
Oil Pressure...............................................3-34
Speedometer..............................................3-24
Voltmeter Gage...........................................3-28
Gasoline
Octane........................................................ 5-5
Specications............................................... 5-5
GM Mobility Reimbursement Program.................. 7-5
H
Hazard Warning Flashers................................... 3-6
Headlamp Wiring............................................5-92
Headlamps....................................................5-47
Bulb Replacement.......................................5-46
Daytime Running Lamps...............................3-14
Flash-to-Pass............................................... 3-9
5