air condition CHEVROLET ASTRO 2004 User Guide

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.
5-21

How to Inspect the Engine Air
Cleaner/Filter
To inspect the engine air cleaner/®lter remove the ®lter
from the vehicle and lightly shake ®lter to release
loose dust and dirt. If the ®lter remains caked with dirt, a
new ®lter is required.
To inspect or replace the ®lter, do the following:
1. Unsnap both clips on the cover.
2. Remove the cover.
3. Change the ®lter.
4. Snap both clips to secure the engine air
cleaner/®lter cover.
{CAUTION:
Operating the engine with the air cleaner/®lter
off can cause you or others to be burned. The
air cleaner not only cleans the air, it helps to
stop ¯ame if the engine back®res. If it is not
there and the engine back®res, you could
be burned. Do not drive with it off, and be
careful working on the engine with the air
cleaner/®lter off.
Notice:If the air cleaner/®lter is off, a back®re can
cause a damaging engine ®re. And, dirt can
easily get into your engine, which will damage it.
Always have the air cleaner/®lter in place when you
are driving.
Automatic Transmission Fluid
When to Check and Change
A good time to check your automatic transmission ¯uid
level is when the engine oil is changed.
Change both the ¯uid and ®lter every 15,000 miles
(25,000 km) if the vehicle is mainly driven under one or
more of these conditions:
·In heavy city traffic where the outside temperature
regularly reaches 90ÉF (32ÉC) or higher.
·In hilly or mountainous terrain.
·When doing frequent trailer towing.
·Uses such as found in taxi, police or delivery
service.
If you do not use your vehicle under any of these
conditions, change the ¯uid and ®lter every 50,000 miles
(83 000 km).
See
Part A: Scheduled Maintenance Services on
page 6-4.
5-22

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
žcoolant 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.
5-36

·If you spill brake ¯uid on your vehicle's painted
surfaces, the paint ®nish can be damaged. Be
careful not to spill brake ¯uid on your vehicle. If
you do, wash it off immediately. See
Appearance
Care on page 5-86.
Brake Wear
Your vehicle has four-wheel disc brakes.
Disc brake pads have built-in wear indicators that make
a high-pitched warning sound when the brake pads
are worn and new pads are needed. The sound
may come and go or be heard all the time your vehicle
is moving (except when you are pushing on the
brake pedal ®rmly).
{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 speci®cations.
Brake linings should always be replaced as complete
axle sets.
See
Brake System Inspection on page 6-29.
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.
5-41

(A) Light Truck (LT-Metric) Tire:The United States
version of a metric tire sizing system. The letter ªLTº as
the ®rst two characters in the tire size means a light
truck tire engineered to standards set by the U. S. Tire
and Rim Association.
(B) Tire Width:The three-digit number indicates the
tire section width in millimeters from sidewall to sidewall.
(C) Aspect Ratio:A two-digit number that indicates
the tire height-to-width measurements. For example, if
the tire size aspect ratio is ª75,º as shown in item ªCº of
the illustration, it would mean that the tire's sidewall is
75% as high as it is wide.(D) Construction Code:A letter code is used to
indicate the type of ply construction in the tire. The letter
ªRº means radial ply construction; the letter ªDº means
diagonal or bias ply construction; and the letter ªBº
means belted-bias ply construction.
(E) Rim Diameter:Diameter of the wheel in inches.
(F) Service Description:The service description
indicates the load range and speed rating of a tire. The
load index can range from 1 to 279. Speed ratings
range from ªAº to ªZº. The light truck tire size example
above shows dual or single tire con®gurations.Tire Terminology and De®nitions
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. Light Truck (LT-Metric) Tire
5-63

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 speci®ed 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 in¯ated and not
overloaded. Excessive speed, underin¯ation, 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.
5-72

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 avaliable 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 your 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.
5-93

Fuse/Circuit
Breaker Usage
3 Courtesy Lamps, Glove Box Lamp,
Dome Reading Lamps, Vanity Mirror
Lamps, Courtesy Lamps
4 Daytime Running Lamps Relay,
Instrument Panel Cluster
5 Rear Defogger
6 Cruise Module, Truck Body Control
Module, Instrument Panel Cluster,
Cruise Control Switch,
Electrochromic Mirror
7 Power Outlets, Subwoofer Ampli®er
8 Crank Circuit Fuse, Park/Neutral
Switch, Starter Enabler Relay
9 License Plate Lamp, Tailamps,
Parking Lamps, Ashtray Lamp,
Panel Lights, Trailer Taillamps, Front
and Rear Sidemarker Lamps, Door
Switch Illumination, Headlamp
Switch Illumination, Rear Seat Audio
Illumination, Truck Body Control
Module
10 Air Bag System
11 Not UsedFuse/Circuit
Breaker Usage
12 Blower Motor, Rear Air Conditioning
Relay Coil, Front Cont. Temp. Door
Motor, HI Blower Relay, Defogger
Timer Coil
13 Cigarette Lighter, Door Lock
Switches, Dutch Door Release
Module
14 Cluster 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
15 Truck Body Module, Headlamp
Relay
16 Front Turn Signals, Rear Turn
Signals, Trailer Turn Signals,
Back-Up Lamps, Brake
Transmission Shift Interlock Solenoid
17 Front Wipers, Front Washer Pump
5-98

Feed Usage
AUX B Up®tter Battery Feed
AUX A Up®tter Accessory Feed
Relays Usage
A/C Relay
(Rear Heat
and A/C)Rear/Heat and Air ConditioningRelays Usage
Up®tter-ACCY
RelayUp®tter Accessory
Starter Enable
RelayStarter
A/C Enable
RelayAir Conditioning
Headlamps
RelayHeadlamps
Fuel Pump
RelayFuel Pump
Fuse/Circuit
BreakerUsage
UPFITTER-
BATTUp®tter Battery Power Stud, Trailer
Wiring Harness
UPFITTER-
ACCYUp®tter 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
5-100

Fuse/Circuit
BreakerUsage
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
ENG-IOxygen Sensors, Camshaft Position
Sensor, Mass Air Flow Sensor,
Evaporative Emission Canister Vent
Solenoid
IGN-E Air Conditioning Enable Relay Coil
ECM-IFuel Injectors 1±6, Crankshaft
Position Sensot, VCM, Coil Driver
Module (EST), Ignition Coil
Blank Not Used
RH HDLMP Right Headlamp
LH Headlamp Left Headlamp
Blank Not Used
Blank Not UsedFuse/Circuit
BreakerUsage
DIODE-1 Air Conditioning
Blank Not Used
Blank Not Used
Blank Not Used
LIGHTINGCourtesy Fuse, Power Adjust
Mirrors Fuse, Truck Body Control
Battery Fuse
BATTPower Accessory Circuit Breaker,
Stop/Hazard Fuse, Auxiliary Power
Fuse, Cigarette Lighter Fuse, Radio
Battery Fuse
IGN A Starter Relay, Ignition Switch
IGN B Ignition Switch
ABSElectronic Brake
Control Module
Blank Not Used
RAP Radio Accessory, Power Windows
HTD MIR/RR
DEFOGRear Window Defogger,Climate
Control Head
5-101