2004 CHEVROLET ASTRO CARGO VAN air condition

Reinstalling the Engine Cover
1. Lift the engine cover into the front of the vehicle
and slide it all the way forward. Make sure the
rubber seal is over the latches.
2. Tighten the two bolts located on the engine cover
to reinstall the cover to the front of the dash.
3. Put the heater duct over the engine cover
studs. Push up on the duct gently until it snaps
into place.
4. Reconnect the electrical connectors.
5. Reconnect the AM radio ground strap.
6. Reinstall the engine cover extension by gently
squeezing the sides and sliding it into place.
Make sure all of the fastener clips engage and
the extension ts properly in place. Reinstall and
tighten the two screws.
7. Reinstall the two nuts to secure the extension
in place.
Engine Air Cleaner/Filter
SeeEngine Compartment Overview on page 5-12for
the location of the engine air cleaner/lter.
When to Inspect the Engine
Air Cleaner/Filter
Inspect the engine air cleaner/lter every
15,000 miles (25 000 km) and replace every
30,000 miles (50 000 km). If you are driving in
dusty/dirty conditions, inspect the lter at each
engine oil change.
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3
6. Start the engine and let it run until you can feel the
upper radiator hose getting hot. Watch out for the
engine cooling fan.
7. By this time, the coolant level inside the radiator
ller neck may be lower. If the level is lower, add
more of the proper DEX-COOL
®coolant mixture
through the ller neck until the level reaches
the base of the ller neck.
Then replace the pressure cap. At any time during
this procedure if coolant begins to ow out of
the ller neck, reinstall the pressure cap. Be sure
the arrow on the pressure cap lines up.
Engine Fan Noise
This vehicle has a clutched engine cooling fan. When
the clutch is engaged, the fan spins faster to provide
more air to cool the engine. In most everyday driving
conditions, the clutch is not fully engaged. This improves
fuel economy and reduces fan noise. Under heavy
vehicle loading, trailer towing and/or high outside
temperatures, the fan speed increases when the clutch
engages. So you may hear an increase in fan noise.
This is normal and should not be mistaken as the
transmission slipping or making extra shifts. It is merely
the cooling system functioning properly. The fan will
slow down when additional cooling is not required and
the clutch disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch disengages.
5-37

{CAUTION:
The brake wear warning sound means that
soon your brakes will not work well. That
could lead to an accident. When you hear
the brake wear warning sound, have your
vehicle serviced.
Notice:Continuing to drive with worn-out brake
pads could result in costly brake repair.
Some driving conditions or climates may cause a brake
squeal when the brakes are rst applied or lightly
applied. This does not mean something is wrong with
your brakes.
Properly torqued wheel nuts are necessary to help
prevent brake pulsation. When tires are rotated, inspect
brake pads for wear and evenly tighten wheel nuts in
the proper sequence to GM torque specications.
Brake linings should always be replaced as complete
axle sets.
SeeBrake System Inspection on page 6-27.
Brake Pedal Travel
See your dealer if the brake pedal does not return
to normal height, or if there is a rapid increase in pedal
travel. This could be a sign of brake trouble.
Brake Adjustment
Every time you make a brake stop, your disc brakes
adjust for wear.
Replacing Brake System Parts
The braking system on a vehicle is complex. Its many
parts have to be of top quality and work well together if
the vehicle is to have really good braking. Your vehicle
was designed and tested with top-quality GM brake parts.
When you replace parts of your braking system — for
example, when your brake linings wear down and you
need new ones put in — be sure you get new approved
GM replacement parts. If you do not, your brakes may no
longer work properly. For example, if someone puts in
brake linings that are wrong for your vehicle, the balance
between your front and rear brakes can change — for the
worse. The braking performance you have come to
expect can change in many other ways if someone puts
in the wrong replacement brake parts.
5-43

Tire Terminology and Denitions
Air Pressure:The amount of air inside the tire pressing
outward on each square inch of the tire. Air pressure
is expressed in pounds per square inch (psi) or
kilopascal (kPa).
Accessory Weight:This means the combined weight
of optional accessories. Some examples of optional
accessories are, automatic transmission, power steering,
power brakes, power windows, power seats, and air
conditioning.
Aspect Ratio:The relationship of a tire’s height to
its width.
Belt:A rubber coated layer of cords that is located
between the plies and the tread. Cords may be made
from steel or other reinforcing materials.
Bead:The tire bead contains steel wires wrapped by
steel cords that hold the tire onto the rim.
Bias Ply Tire:A pneumatic tire in which the plies are
laid at alternate angles less than 90 degrees to the
centerline of the tread.
Cold Ination Pressure:The amount of air pressure
in a tire, measured in pounds per square inch (psi)
or kilopascals (kPa) before a tire has built up heat from
driving. SeeInation - Tire Pressure on page 5-70.Curb Weight:This means the weight of a motor
vehicle with standard and optional equipment including
the maximum capacity of fuel, oil and coolant, but
without passengers and cargo.
DOT Markings:A code molded into the sidewall of a
tire signifying that the tire is in compliance with the
U.S. Department of Transportation motor vehicle safety
standards. The DOT code includes the Tire Identication
Number (TIN), an alphanumeric designator which can
also identify the tire manufacturer, production plant,
brand and date of production.
GVWR:Gross Vehicle Weight Rating, seeLoading
Your Vehicle on page 4-29.
GAWR FRT:Gross Axle Weight Rating for the front
axle, seeLoading Your Vehicle on page 4-29.
GAWR RR:Gross Axle Weight Rating for the rear axle,
seeLoading Your Vehicle on page 4-29.
Intended Outboard Sidewall:The side of an
asymmetrical tire, that must always face outward when
mounted on a vehicle.
Kilopascal (kPa):The metric unit for air pressure.
There are 6.9 kPa’s to one psi.
Light Truck (LT-Metric) Tire:A tire used on light duty
trucks and some multipurpose passenger vehicles.
5-68

Temperature – A, B, C
The temperature grades are A (the highest), B, and C,
representing the tire’s resistance to the generation
of heat and its ability to dissipate heat when tested
under controlled conditions on a specied indoor
laboratory test wheel. Sustained high temperature
can cause the material of the tire to degenerate and
reduce tire life, and excessive temperature can lead
to sudden tire failure. The grade C corresponds to
a level of performance which all passenger car tires
must meet under the Federal Motor Vehicle Safety
Standard No. 109. Grades B and A represent higher
levels of performance on the laboratory test wheel
than the minimum required by law.
Warning: The temperature grade for this tire is
established for a tire that is properly inated and
not overloaded. Excessive speed, underination, or
excessive loading, either separately or in combination,
can cause heat buildup and possible tire failure.
Wheel Alignment and Tire Balance
The wheels on your vehicle were aligned and balanced
carefully at the factory to give you the longest tire life
and best overall performance.
Scheduled wheel alignment and wheel balancing are
not needed. However, if you notice unusual tire wear
or your vehicle pulling one way or the other, the
alignment may need to be reset. If you notice your
vehicle vibrating when driving on a smooth road, your
wheels may need to be rebalanced.
Wheel Replacement
Replace any wheel that is bent, cracked or badly
rusted or corroded. If wheel nuts keep coming loose,
the wheel, wheel bolts and wheel nuts should be
replaced. If the wheel leaks air, replace it (except some
aluminum wheels, which can sometimes be repaired).
See your dealer if any of these conditions exist.
Your dealer will know the kind of wheel you need.
Each new wheel should have the same load-carrying
capacity, diameter, width, offset and be mounted
the same way as the one it replaces.
5-75

Cleaning Tires
To clean your tires, use a stiff brush with tire cleaner.
Notice:Using petroleum-based tire dressing
products on your vehicle may damage the paint
nish and/or tires. When applying a tire dressing,
always wipe off any overspray from all painted
surfaces on your vehicle.
Sheet Metal Damage
If the vehicle is damaged and requires sheet metal
repair or replacement, make sure the body repair shop
applies anti-corrosion material to parts repaired or
replaced to restore corrosion protection.
Original manufacturer replacement parts will provide
the corrosion protection while maintaining the warranty.
Finish Damage
Any stone chips, fractures or deep scratches in the
nish should be repaired right away. Bare metal
will corrode quickly and may develop into major
repair expense.
Minor chips and scratches can be repaired with touch-up
materials available from your dealer. Larger areas of
nish damage can be corrected in your dealer’s
body and paint shop.
Underbody Maintenance
Chemicals used for ice and snow removal and dust
control can collect on the underbody. If these are
not removed, corrosion and rust can develop on the
underbody parts such as fuel lines, frame, oor pan,
and exhaust system even though they have
corrosion protection.
At least every spring, ush these materials from the
underbody with plain water. Clean any areas where
mud and debris can collect. Dirt packed in close areas
of the frame should be loosened before being ushed.
Your dealer or an underbody car washing system can
do this for you.
Chemical Paint Spotting
Some weather and atmospheric conditions can create
a chemical fallout. Airborne pollutants can fall upon and
attack painted surfaces on the vehicle. This damage can
take two forms: blotchy, ring-shaped discolorations, and
small, irregular dark spots etched into the paint surface.
Although no defect in the paint job causes this, GM
will repair, at no charge to the owner, the surfaces
of new vehicles damaged by this fallout condition within
12 months or 12,000 miles (20 000 km) of purchase,
whichever occurs rst.
5-97

Fuse/Circuit
BreakerUsage
11 Not Used
12Blower Motor, Rear Air Conditioning
Relay Coil, Front Cont. Temp.
Door Motor, HI Blower Relay,
Defogger Timer Coil
13Cigarette Lighter, Door Lock
Switches, Dutch Door
Release Module
14Cluster Illumination, Climate
Controls, Chime Module, Radio
Illumination, Rear Heat Switch
Illumination, Rear Wiper/Washer
Switch Illumination, Rear Liftgate
Switch Illumination, Remote
Cassette Illumination,
Overhead Console, Truck Body
Control Illumination
15Truck Body Module,
Headlamp Relay
16Front Turn Signals, Rear
Turn Signals, Trailer Turn
Signals, Back-Up Lamps,
Brake Transmission Shift
Interlock SolenoidFuse/Circuit
BreakerUsage
17 Front Wipers, Front Washer Pump
18VCM-Ign 3, VCM-Brake,
Cruise Stepper Motor Signal,
ATC Module
19Instrument Panel Radio: ATC
(Main Feed), 2000 Series (Standby)
20PRNDL/Odometer, Shift A and
Shift B Solenoids, 3–2 Downshift
Solenoid, Instrument Panel Cluster,
VCM Module
21 Powr Adjust Mirrors
22 Not Used
23 Rear Wiper, Rear Washer Pump
24 Not Used
A(Circuit Breaker) Power Door
Lock Relay, 6–Way Power Seats
B (Circuit Breaker) Power Windows
5-103

Relays Usage
A/C Relay
(Rear Heat
and A/C)Rear/Heat and Air Conditioning
Uptter-ACCY
RelayUptter Accessory
Starter Enable
RelayStarter
A/C Enable
RelayAir Conditioning
Headlamps
RelayHeadlamps
Fuel Pump
RelayFuel PumpFuse/Circuit
BreakerUsage
UPFITTER-
BATTUptter Battery Power Stud,
Trailer Wiring Harness
UPFITTER-
ACCYUptter Accessory Relay
Spare Not used
Spare Not used
Spare Not used
ECM-1BFuel Pump Relay and Motor,
VCM, Oil Pressure Switch/Sender
HORN Horn Relay and Horn
A/C COMPAir Conditioning Enable Relay
and Compressor
RR HTR/AC Rear Heater and Air Conditioning
ATC Active Transfer Case-L Van
FRT HVAC Front Heater and Air Conditioning
5-105