brake CHEVROLET AVALANCHE 2004 1.G Repair Manual

Turn Signals When Towing a Trailer
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, if necessary, a lower gear
selection if the transmission shifts too often (e.g.,
under heavy loads and/or hilly conditions).You may also want to activate the tow/haul mode if the
transmission shifts too often. See “Tow/Haul Mode”
earlier in this section.
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 5-29.
4-77

Parking on Hills
{CAUTION:
You really should not park your vehicle, with a
trailer attached, on a hill. If something goes
wrong, your rig could start to move. People
can be injured, and both your vehicle and the
trailer can be damaged.
But if you ever have to park your rig on a hill, here’s
how to do it:
1. Apply your regular brakes, but don’t shift into
PARK (P) yet.
2. Have someone place chocks under the trailer
wheels.
3. When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your
parking brake and shift into PARK (P).
5. If you have a four-wheel-drive vehicle, be sure the
transfer case is in a drive gear and not in
NEUTRAL (N).
6. Release the regular brakes.
{CAUTION:
It can be dangerous to get out of your vehicle if
the shift lever is not fully in PARK (P) with the
parking brake rmly set. Your vehicle can roll.
If you have left the engine running, the vehicle
can move suddenly. You or others could be
injured. To be sure your vehicle will not move,
even when you are on fairly level ground, use
the steps that follow.
Always put the shift lever fully in PARK (P) with
the parking brake rmly set.
If the transfer case on four-wheel-drive vehicles
is in NEUTRAL, your vehicle will be free to roll,
even if your shift lever is in PARK (P). So, be
sure the transfer case is in a drive gear — not in
NEUTRAL.
4-78

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

Service............................................................5-3
Doing Your Own Service Work.........................5-4
Adding Equipment to the Outside
of Your Vehicle...........................................5-5
Fuel................................................................5-5
Gasoline Octane............................................5-5
Gasoline Specications....................................5-5
California Fuel...............................................5-6
Additives.......................................................5-6
Fuels in Foreign Countries...............................5-7
Filling Your Tank............................................5-7
Filling a Portable Fuel Container.......................5-9
Checking Things Under the Hood....................5-10
Hood Release..............................................5-10
Engine Compartment Overview.......................5-12
Engine Oil...................................................5-16
Engine Air Cleaner/Filter................................5-21
Automatic Transmission Fluid.........................5-23
Engine Coolant.............................................5-26
Coolant Surge Tank Pressure Cap..................5-29
Engine Overheating.......................................5-29
Cooling System............................................5-33Engine Fan Noise.........................................5-40
Power Steering Fluid.....................................5-41
Windshield Washer Fluid................................5-42
Brakes........................................................5-43
Battery........................................................5-47
Jump Starting...............................................5-48
Rear Axle.......................................................5-55
Four-Wheel Drive............................................5-56
Front Axle......................................................5-57
Bulb Replacement..........................................5-58
Halogen Bulbs..............................................5-58
Headlamps..................................................5-58
Front Turn Signal, Sidemarker and
Parking Lamps..........................................5-62
Front Turn Signal, Sidemarker and
Daytime Running Lamps.............................5-63
Daytime Running Lamps................................5-65
Center High-Mounted Stoplamp (CHMSL).........5-65
Taillamps.....................................................5-65
Replacement Bulbs.......................................5-66
Windshield Wiper Blade Replacement..............5-67
Section 5 Service and Appearance Care
5-1

Checking Things Under
the Hood
{CAUTION:
Things that burn can get on hot engine parts
and start a re. These include liquids like fuel,
oil, coolant, brake uid, windshield washer and
other uids, and plastic or rubber. You or
others could be burned. Be careful not to drop
or spill things that will burn onto a hot engine.
Hood Release
To open the hood, do the following:
1. Pull the handle located
inside the vehicle to
the lower left of
the steering wheel.
5-10

A. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 5-21.
B. Coolant Surge Tank. SeeCooling System on
page 5-33andCoolant Surge Tank Pressure Cap
on page 5-29.
C. Air Filter Restriction Indicator (If Equipped). See
Engine Air Cleaner/Filter on page 5-21.
D. Engine Oil Fill. SeeEngine Oil on page 5-16.
E. Engine Oil Dipstick. SeeEngine Oil on page 5-16.
F. Automatic Transmission Dipstick. SeeAutomatic
Transmission Fluid on page 5-23.
G. Fan. SeeCooling System on page 5-33andEngine
Fan Noise on page 5-40.H. Remote Negative (−) Terminal (GND). SeeJump
Starting on page 5-48.
I. Power Steering Fluid Reservoir (Out of View). See
Power Steering Fluid on page 5-41.
J. Remote Positive (+) Terminal. SeeJump Starting on
page 5-48.
K. Brake Fluid Reservoir. SeeBrakes on page 5-43.
L. Underhood Fuse Block. See “Underhood Fuse Block”
underFuses and Circuit Breakers on page 5-120.
M. Battery. SeeBattery on page 5-47.
N. Windshield Washer Fluid Reservoir. SeeWindshield
Washer Fluid on page 5-42.
5-13

A. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 5-21.
B. Coolant Surge Tank. SeeCooling System on
page 5-33andCoolant Surge Tank Pressure Cap
on page 5-29.
C. Air Filter Restriction Indicator (If Equipped). See
Engine Air Cleaner/Filter on page 5-21.
D. Engine Oil Dipstick. SeeEngine Oil on page 5-16.
E. Automatic Transmission Dipstick. SeeAutomatic
Transmission Fluid on page 5-23.
F. Engine Oil Fill. SeeEngine Oil on page 5-16.
G. Fan. SeeCooling System on page 5-33andEngine
Fan Noise on page 5-40.
H. Remote Negative (−) Terminal (GND). SeeJump
Starting on page 5-48.I. Remote Positive (+) Terminal. SeeJump Starting on
page 5-48.
J. Power Steering Fluid Reservoir. SeePower Steering
Fluid on page 5-41.
K. Brake Fluid Reservoir. SeeBrakes on page 5-43.
L. Underhood Fuse Block. See “Underhood Fuse Block”
underFuses and Circuit Breakers on page 5-120.
M. Battery. SeeBattery on page 5-47.
N. Windshield Washer Fluid Reservoir. SeeWindshield
Washer Fluid on page 5-42.
5-15

How to Check
Because this operation can be a little difficult, you may
choose to have this done at the dealership service
department.
If you do it yourself, be sure to follow all the instructions
here, or you could get a false reading on the dipstick.
Notice:Too much or too little uid can damage
your transmission. Too much can mean that some
of the uid could come out and fall on hot engine
part or exhaust system parts, starting a re.
Too little uid could cause the transmission to
overheat. Be sure to get an accurate reading if you
check your transmission uid.
Wait at least 30 minutes before checking the
transmission uid level if you have been driving:
When outside temperatures are above 90°F (32°C).
At high speed for quite a while.
In heavy traffic – especially in hot weather.
While pulling a trailer.
To get the right reading, the uid should be at
normal operating temperature, which is 180°F to
200°F (82°C to 93°C).Get the vehicle warmed up by driving about
15 miles (24 km) when outside temperatures are above
50°F (10°C). If it’s colder than 50°F (10°C), drive the
vehicle in THIRD (3) until the engine temperature gage
moves and then remains steady for 10 minutes.
A cold uid check can be made after the vehicle has
been sitting for eight hours or more with the engine off,
but this is used only as a reference. Let the engine
run at idle for ve minutes if outside temperatures are
50°F (10°C) or more. If it’s colder than 50°F (10°C), you
may have to idle the engine longer. Should the uid
level be low during this cold check, youmustcheck the
uid hot before adding uid. Checking the uid hot
will give you a more accurate reading of the uid level.
Checking the Fluid Level
Prepare your vehicle as follows:
Park your vehicle on a level place. Keep the engine
running.
With the parking brake applied, place the shift lever
in PARK (P).
With your foot on the brake pedal, move the shift
lever through each gear range, pausing for about
three seconds in each range. Then, position the shift
lever in PARK (P).
Let the engine run at idle for three minutes or more.
5-24

Open the cap with the washer symbol on it. Add washer
uid until the tank is full.
Notice:
When using concentrated washer uid, follow
the manufacturer’s instructions for adding
water.
Do not mix water with ready-to-use washer uid.
Water can cause the solution to freeze and
damage your washer uid tank and other parts
of the washer system. Also, water does not
clean as well as washer uid.
Fill your washer uid tank only three-quarters
full when it is very cold. This allows for
expansion if freezing occurs, which could
damage the tank if it is completely full.
Do not use engine coolant (antifreeze) in your
windshield washer. It can damage your washer
system and paint.
Brakes
Brake Fluid
Your brake master cylinder reservoir is lled with DOT-3
brake uid. SeeEngine Compartment Overview on
page 5-12for the location of the reservoir.
There are only two reasons why the brake uid level in
the reservoir might go down. The rst is that the
brake uid goes down to an acceptable level during
normal brake lining wear. When new linings are put in,
the uid level goes back up. The other reason is
that uid is leaking out of the brake system. If it is, you
should have your brake system xed, since a leak
means that sooner or later your brakes will not work
well, or will not work at all.
5-43