2004 CHEVROLET AVALANCHE wiring

Midgate
{CAUTION:
It can be dangerous to drive with the cargo
area covered and the tailgate and the midgate
open because carbon monoxide (CO) gas can
come into your vehicle. You can not see or
smell CO. It can cause unconsciousness and
even death. If you must drive with the cargo
covers on and the tailgate and midgate open
or if electrical wiring or other cable
CAUTION: (Continued)
CAUTION: (Continued)
connections must pass through the seal
between the body and the midgate:
Make sure all windows are shut.
Turn the fan on your heating or cooling
system to its highest speed on the setting
that brings in outside air. This will force
outside air into your vehicle. See
Automatic Climate Control System on
page 3-22.
If you have air outlets on or under the
instrument panel, open them all the way.
SeeEngine Exhaust on page 2-47.
Midgate Operation
Your vehicle is equipped with a midgate and a
removable rear glass panel. The midgate allows you to
extend the length of your vehicle’s cargo area.
2-14

Auxiliary Roof Mounted Lamp Switch
If your vehicle has this feature, this button includes
wiring provisions for a dealer or a qualied service
center to install an auxiliary roof lamp.
This button is located on
the center of the
instrument panel near the
comfort controls.
When the button wiring is connected to an auxiliary
roof-mounted lamp, pressing the button will activate
the lamp and illuminate an indicator light near the button.
Pressing the button again will turn off the roof
mounted lamp.
If your vehicle has this button, your vehicle may have
the snow plow prep package. For further information see
Adding a Snow Plow or Similar Equipment on
page 4-63.
Cargo Lamps
You can use the cargo lamps if you need more light in
the cargo area of your vehicle or in the top-box
storage units. Some vehicles will only have a cargo
lamp in the passenger side top box.
Press the button, with this
symbol to turn the cargo
lamps on or off.
The cargo lamps symbol light will come on in the
instrument panel cluster when the cargo lamps are on
and the ignition key is turned to run.
3-19

Safety Belt Reminder Light
When the key is turned to RUN or START, a chime 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 chime
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 sensors, the air
bag modules, the wiring and the crash sensing and
diagnostic module. For more information on the air bag
system, seeAir Bag Systems on page 1-51.
3-36

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, belts, 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
Heavy-Duty Trailer Wiring Package
Your vehicle is equipped with the eight-wire trailer
towing harness. This harness with a seven-pin universal
heavy-duty trailer connector is attached to a bracket
on the hitch platform.
The Center High-Mounted Stoplamp (CHMSL) wire is tied
next to the trailer wiring harness for use with a trailer.
4-79

The eight-wire harness contains the following trailer
circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn Signal
Brown: Taillamps
White: Ground
Light Green: Back-up Lamps
Light Blue: CHMSL
Red: Battery Feed
Dark Blue: Trailer Brake
A jumper harness for an electric trailer brake controller
and a trailer battery feed fuse may be included with
this trailering package. See “Instrument Panel Jumper
Wiring Harness” later in this section.
If you need to tow a light-duty trailer with a standard
four-way, round pin connector, an adapter may be
included. See “Four-Wire Harness Adapter” later in
this section.
Instrument Panel Jumper Wiring Harness
This harness may be included with your vehicle as part
of the heavy-duty trailer wiring package.
This harness is for an electric brake controller and
includes a trailer battery feed fuse. It should be installed
by your dealer or a qualied service center.
4-80

Four-Wire Harness Adapter
This adapter may be
included with your vehicle
as part of the heavy-duty
trailer wiring package.
Use this adapter to connect a standard four-way round
pin connector to the seven-wire harness on your vehicle.Connect the adapter with the tab pointing up. Then ip
cap on the vehicle’s seven-wire harness will lock
onto the tab and help hold the adapter in place. Plug
the four-way round pin connector onto the adapter.
4-81

Windshield Wiper Fuses
The windshield wiper motor is protected by an internal
circuit breaker and a fuse. If the motor overheats due to
heavy snow, etc., the wiper will stop until the motor
cools. If the overload is caused by some electrical
problem and not snow, etc., be sure to get it xed.
Power Windows and Other Power
Options
Circuit breakers protect the power windows and other
power accessories. When the current load is too heavy,
the circuit breaker opens and closes, protecting the
circuit until the problem is xed or goes away.
Fuses and Circuit Breakers
The wiring circuits in your vehicle are protected from
short circuits by a combination of fuses, circuit breakers
and fusible thermal links. 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.If you ever have a problem on the road and don’t have
a spare fuse, you can borrow one that has the same
amperage. Just pick some feature of your vehicle
that you can get along without – like the radio or
cigarette lighter – and use its fuse, if it is the correct
amperage. Replace it as soon as you can.
Instrument Panel Fuse Block
The fuse block access
door is on the driver’s side
edge of the instrument
panel. Pull off the cover to
access the fuse block.
To remove fuses if you don’t have a fuse extractor, hold
the end of the fuse between your thumb and index
nger and pull straight out.
You may have spare fuses located behind the fuse
block access door. These can be used to replace a bad
fuse. However, make sure it is of the correct amperage.
5-120

Fuses Usage
VEH CHMSLVehicle and Trailer High
Mounted Stoplamp
LT TRLR ST/TRN Left Turn Signal/Stop Trailer
LT TRNLeft Turn Signals and
Sidemarkers
VEH STOPVehicle Stoplamps, Brake
Module, Electronic Throttle
Control Module
Body Harness Connector
RT TRLR ST/TRN Right Turn Signal/Stop Trailer
RT TRNRight Turn Signals and
Sidemarkers
DDM Driver Door Module
AUX PWR 2Rear Cargo Area Power
Outlets
LOCKS Power Door Lock System
ECCRear Electronic Climate
Control, Liftgate
TBC 2C Truck Body Controller
FLASH Flasher Module
CB LT DOORSLeft Power Window Circuit
Breaker
TBC 2B Truck Body Controller
TBC 2A Truck Body ControllerCenter Instrument Panel Fuse Block
The center instrument panel utility block is located
underneath the instrument panel, to the left of the
steering column.
Device Usage
SEO Special Equipment Option
TRAILER Trailer Brake Wiring
UPFIT Uptter (Not Used)
SL RIDERide Control Harness
Connection
5-122