2002 CHEVROLET EXPRESS wiring

2-16
Rear Doors
CAUTION:
It can be dangerous to drive with the rear door(s)
or rear swing
-out windows open because carbon
monoxide (CO) gas can come into your vehicle.
You can't see or smell CO. It can cause
unconsciousness and even death.
CAUTION: (Continued)
CAUTION: (Continued)
If you must drive with the rear door(s) or rear
swing
-out windows open or if electrical wiring or
other cable connections must pass through the
seal between the body and the rear door(s) or
rear swing
-out windows:

Make sure all other windows are shut.

Turn the fan on your heating or cooling
system to its highest speed with the setting
on VENT, HEAT or DEFOG. Additionally,
on vehicles with heating/air conditioning
systems, MAX A/C or BI
-LEVEL A/C can
be used. That will force outside air into
your vehicle. See ªComfort Controlsº in
the Index.

If you have air outlets on or under the
instrument panel, open them all the way.
See ªEngine Exhaustº in the Index.

2-41
Exterior Lamps
The exterior lamp control is located on the driver's side
of the instrument panel.The exterior lamp control has three positions:
OFF: Turning the control to this position turns off all
lamps except the Daytime Running Lamps (DRL).
(Parking Lamps): Turning the control to
this position turns on the parking lamps, together with
the following:

Sidemarker Lamps

Taillamps

License Plate Lamps

Instrument Panel Lights

Ashtray Lamp
(Headlamps): Turning the control to this position
turns on the headlamps, together with the previously
listed lamps and lights.
You can change your headlamps from high to low beam
by pulling on the turn signal/high beam lever.
A circuit breaker protects your headlamps. If you have
an electrical overload, your headlamps will flicker on
and off. Have your headlamp wiring checked right away
if this happens.

2-56
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 tone will
come on for about eight 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 about 20 seconds,
then it will flash for about
55 seconds.
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 AIR BAG or 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, see ªAir Bagº in the Index.
United States Canada
This light will come on when you start your vehicle, and
it will flash for a few seconds. Then the light should go
out. This means the system is ready.

3-8 Rear Window Defogger (If Equipped)
If you see lines running across the rear windows, your
vehicle has a rear window defogger. The lines warm
the glass.
For best results, clear the windows of as much snow or
ice as possible before using the rear window defogger.
To turn on the rear window
defogger, press this button
located near the fan control.
An indicator light in the
button will come on when
the rear window defogger
is working.
The rear window defogger will only work when the
ignition is in RUN.The rear window defogger will turn itself off after
several minutes. If you need additional warming time,
press the button again. Pressing the button when the
indicator light is illuminated will turn the defogger off.
If your vehicle is equipped with heated outside rearview
mirrors, the rear window defogger button will activate
both the rear window defogger and the heated outside
rearview mirrors. See ªHeated Outside Rearview
Mirrorsº in the Index.
Do not attach a temporary vehicle license, tape or decals
across the defogger grid on the rear windows. Use care
not to damage the wiring bands that connect the rear
window defogger grid when operating the rear
swing
-out windows (if equipped).
NOTICE:
Don't use a razor blade or something else sharp
on the inside of the rear window. If you do, you
could cut or damage the warming grid, and the
repairs wouldn't be covered by your warranty.

4-36 Total Weight on Your Vehicle's Tires
Be sure your vehicle's tires are inflated to the upper
limit for cold tires. You'll find these numbers on the
Certification label at the rear edge of the driver's door or
see ªLoading Your Vehicleº in the Index. Then be sure
you don't go over the GVW limit for your vehicle,
including the weight of the trailer tongue.
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. Here are
some rules to follow:

The bumpers on your vehicle are not intended
for hitches. Do not attach rental hitches or other
bumper
-type hitches to them. Use only a
frame
-mounted hitch that does not attach to the
bumper. Do not use a ball hitch, because it could
pull the bumper loose.
If you'll be pulling a trailer that, when loaded, will
weigh more than 4,000 lbs. (1 800 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.

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 by the
factory
-installed hitch, 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. See ªCarbon Monoxideº in the
Index. Dirt and water can, too.

4-40 Turn Signals When Towing a Trailer
When you tow a trailer, your vehicle has to have extra
wiring and a heavy
-duty turn signal flasher (included in
the optional trailering package).
The arrows on your instrument panel will flash
whenever you signal a turn or lane change. Properly
hooked up, the trailer lamps will also flash, telling other
drivers you're about to turn, change lanes or stop.
When towing a trailer, the arrows on your instrument
panel will flash 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 gear before you 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.
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, see ªEngine Overheatingº in
the Index.

4-42 Trailer Wiring Harness
The optional heavy-duty trailer wiring package is a
seven
-wire harness assembly. The four-wire portion of
the harness assembly is stored under the vehicle, along
the driver's side rear corner of the frame rail. The
three
-wire portion of the harness assembly is stored
in a frame pocket under the rear of the vehicle, on the
driver's side. The heavy
-duty trailer wiring harness
has a 30
-amp feed wire. Both harnesses come without
connectors and should be wired by a qualified electrical
technician. The technician can use the following color
code chart when connecting the wiring harness to
your trailer.Four
-Wire Harness

Light Green: Back
-up lamps

Brown: Parking lamps

Yellow: Left stoplamp and turn signal

Dark Green: Right stoplamp and turn signal
Three
-Wire Harness

Dark Blue: Use for electric trailer brakes
(seven
-wire harness only)

Orange: Trailer accessory (seven
-wire harness only)

White (heavy gage): Ground wire
Securely attach the harness to the trailer, then tape or
strap it to your vehicle's frame rail. Be sure you leave it
loose enough so the wiring doesn't bend or break, but
not so loose that it drags on the ground. Store the
harness in its original place. Wrap the harness together
and tie it neatly so it won't be damaged.

6-62
Electrical System
Add-On Electrical Equipment
NOTICE:
Don't add anything electrical to your vehicle
unless you check with your dealer first. 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 ªServicing
Your Air Bag
-Equipped Vehicleº in the Index.
Headlamp Wiring
The headlamp wiring is protected by a circuit breaker in
the lamp switch. An electrical overload will cause the
lamps to flicker 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 fixed.