2004 CHEVROLET EXPRESS CARGO VAN wiring

The headlamps can be switched from high to low-beam
by pulling the turn signal/high-beam lever
A circuit breaker protects the headlamps. If there is an
electrical overload, the headlamps will icker on and
off. Have the headlamp wiring checked right away if this
happens.
Lamps On Reminder
A reminder chime will sound when the control is turned
to the headlamps or parking lamps position, the key
is out of the ignition, and the driver’s door is open.
To disable the chime, turn the control to the DRL
position and then back to the parking lamps or
headlamps position.
Daytime Running Lamps
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 the DRL mode and
not in the defeat position.
When the DRL are on, only the headlamps will be on.
The taillamps, sidemarker, and other lamps will not
be on. The instrument panel will be lit.
When the headlamp switch is turned off, the headlamps
will go off, and the DRL lamps will come on.
Turn the exterior lamp control to the defeat position or
shift into PARK (P). The DRL will stay off until the control
is turned to the defeat position, or the vehicle is shifted
out of PARK (P).
This procedure applies only to vehicles rst sold in the
United States.
3-15

Safety Belt Reminder Light
When the key is turned to RUN or START, a tone will
come on for several seconds to remind people to fasten
their safety belts, unless the driver’s safety belt is
already buckled.
The safety belt light will
also come on and stay on
for several seconds, then it
will ash for several more.
If the driver’s belt is already buckled, neither the tone
nor the light will come on.
Air Bag Readiness Light
There is an air bag readiness light on the instrument
panel, which shows the air bag 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 sensor, the air
bag modules, the wiring and the crash sensing and
diagnostic module. For more information on the air bag
system, seeAir Bag System on page 1-70.
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.
3-27

Hitches
It’s important to have the correct hitch equipment.
Crosswinds, large trucks going by and rough roads are
a few reasons why you’ll need the right hitch.
Weight-Distributing Hitches and Weight
Carrying Hitches
When using a weight-distributing hitch, the hitch must
be adjusted so that the distance (A) remains the
same both before and after coupling the trailer to the
tow vehicle.If you use a step-bumper hitch, your bumper could be
damaged in sharp turns. Make sure you have ample
room when turning to avoid contact between the trailer
and the bumper.
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 2-30. (A) Body to Ground Distance, (B) Front of Vehicle
4-46

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.
Driving On Grades
Reduce speed and shift to a lower gearbeforeyou start
down a long or steep downgrade. If you don’t shift
down, you might have to use your brakes so much that
they would get hot and no longer work well.
You can tow in DRIVE (D). You may want to shift the
transmission to THIRD (3) or a lower gear under heavy
loads and/or hilly conditions.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a lower
temperature than at normal altitudes. If you turn your
engine off immediately after towing at high altitude
on steep uphill grades, your vehicle may show signs
similar to engine overheating. To avoid this, let the
engine run while parked (preferably on level ground)
with the automatic transmission in PARK (P) for a
few minutes before turning the engine off. If you do get
the overheat warning, seeEngine Overheating on
page 5-26.
4-49

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 HarnessLight 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 Stop/CHMSL
4-51

Tires..............................................................5-58
Ination - Tire Pressure.................................5-66
Dual Tire Operation.......................................5-67
Tire Inspection and Rotation...........................5-68
When It Is Time for New Tires.......................5-69
Buying New Tires.........................................5-70
Uniform Tire Quality Grading..........................5-71
Wheel Alignment and Tire Balance..................5-72
Wheel Replacement......................................5-72
Tire Chains..................................................5-74
If a Tire Goes Flat........................................5-75
Changing a Flat Tire.....................................5-76
Appearance Care............................................5-92
Cleaning the Inside of Your Vehicle.................5-92
Care of Safety Belts......................................5-95
Weatherstrips...............................................5-95Cleaning the Outside of Your Vehicle..............5-95
Sheet Metal Damage.....................................5-98
Finish Damage.............................................5-98
Underbody Maintenance................................5-98
Chemical Paint Spotting.................................5-98
Vehicle Care/Appearance Materials..................5-99
Vehicle Identication.....................................5-100
Vehicle Identication Number (VIN)................5-100
Service Parts Identication Label...................5-100
Electrical System..........................................5-101
Add-On Electrical Equipment.........................5-101
Headlamp Wiring........................................5-101
Windshield Wiper Fuses...............................5-101
Fuses and Circuit Breakers..........................5-102
Capacities and Specications........................5-106
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 Air Bag-Equipped Vehicle on page 1-80.
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.
5-101

Fuse Usage
22 Front Park Lamp
32 Auxiliary1
33 Auxiliary2
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 Pass Unlock
Circuit Breaker Usage
34 Power WindowEngine Compartment Fuse Block
The fuse block is 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 Backup Lamps Trailer WiringFront of Vehicle
5-103