trailer CHEVROLET ASTRO 2003 Owner's Manual

Trailer Wiring Harness
If you have the optional trailering package, your vehicle
will have an eight-wire harness, including the center
high-mounted stoplamp battery feed wire. The harness
is stored on the passenger’s side of the vehicle near
the rear wheel well. This harness has a
30 amp battery
feed wire and no connector, and should be wired by
a qualified electrical technician. After choosing an
aftermarket trailer mating connector pair, have the
technician attach one connector to the eight-wire trailer
harness and the other connector to the wiring harness
on the trailer. Be sure the wiring harness on the trailer
is
taped or strapped to the trailer’s frame rail and leave
it loose enough
so the wiring doesn’t bend or break, but
not
so loose that it drags on the ground. The eight-wire
harness must be routed out of your vehicle between
the rear door and the floor, with enough of the harness
left on both sides
so that the trailer or the body won’t
pull it. If you do not have the optional trailering
package, your vehicle will still have a trailering harness.
The harness is located near the passenger’s side
rear wheel well. It consists
of six wires that may be
used by after-market trailer hitch installers. The
technician can use the following color code chart
when connecting the wiring harness to your trailer.
e
e
Brown: Rear lamps.
Yellow: Left stoplamp and turn signal.
Dark Green: Right stoplamp and turn signal.
White (Heavy Gage): Ground.
Light Green: Back-up lamps.
White (Light Gage): Center High-Mounted Stoplamp.
Blue: Auxiliary circuit (eight-wire harness only).
Orange: Fused auxiliary (eight-wire harness only).
Store the harness in its original place. Wrap the
harness together and tie it neatly
so it won’t
be damaged.
4-4 1

As in the chart shown previously, SAE 5W-30 is the
only viscosity grade recommended for your vehicle.
You should look for and use only oils which have the
API Starburst symbol and which are also identified
as SAE 5W-30.
If you cannot find such SAE 5W-30 oils,
you can use an SAE IOW-30 oil which has the API
Starburst symbol,
if it's going to be 0°F (-18°C)
or above.
Do not use other viscosity grade oils, such as
SAE 1OW-40 or SAE 20W-50 under any conditions.
Notice: Use only engine oil with the American
Petroleum Institute Certified For Gasoline Engines
starburst symbol. Failure to use the recommended
oil can result in engine damage not covered by
your warranty.
GM Goodwrench@ oil meets all the requirements for
your vehicle.
If you are in an area of extreme cold, where the
temperature falls below -20°F (-29"C), it is
recommended that you use either an SAE 5W-30
synthetic oil or an SAE OW-30 oil. Both will provide
easier cold starting and better protection for your engine
at extremely low temperatures.
Engine Oil Additives
Don't add anything to your oil. The recommended oils
with the starburst symbol are all you will need for
good performance and engine protection.
When to Change Engine Oil
If any one of these are true for you, use the short
tripkity maintenance schedule:
e
e
e
Most trips are less than 5 miles (8 km). This is
particularly important when outside temperatures
are below freezing.
Most trips include extensive idling (such as frequent
driving in stop-and-go traffic).
You frequently tow a trailer or use a carrier on top
of your vehicle.
The vehicle is used for delivery service, police, taxi
or other commercial application.
5-1
8

Automatic Transmission Fluid
When to Check and Change
A good time to check your automatic transmission fluid
level is when the engine oil is changed.
Change both the fluid and filter 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
In hilly or mountainous terrain.
When doing frequent trailer towing.
Uses such as found in taxi, police or delivery
If you do not use your vehicle under any of these
conditions, change the fluid and filter every
50,000 miles (83 000 km).
See
Part A: Scheduled Maintenance Services on
page
6-4.
regularly reaches 90°F (32°C) or higher.
service.
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.
Notices Too much or too little fluid can damage
your transmission.
Too much can mean that some
of the fluid could come out and fall on hot engine
part or exhaust system parts, starting a fire.
Too little fluid could cause the transmission to
overheat. Be sure to get an accurate reading if you
check your transmission fluid.
Wait at least 30 minutes before checking the
transmission fluid level
if you have been driving:
When outside temperatures are above 90°F (32°C).
0 At high speed for quite a while.
In heavy traffic
- especially in hot weather.
While pulling a trailer.
To get the right reading, the fluid should be at normal
operating temperature, which is 180°F to 200°F
(82°C to 93°C).
5-25

If No Steam Is Coming From
Your Engine
If you get an engine overheat warning but see or
hear no steam, the problem may not be too serious.
Sometimes the engine can get a little too hot when you:
Climb a long hill on a hot day.
Stop after high-speed driving.
Idle for long periods in traffic.
Tow a trailer. See ”Driving on Grades” in Towing a
Trailer on page 4-3 I.
If you get the overheat warning with no sign of steam,
try this for a minute or
so:
1. In heavy traffic, let the engine idle in NEUTRAL (N)
while stopped. If it is safe to do so, pull off the road,
shift to PARK (P) or NEUTRAL
(N) and let the
engine idle.
If you no longer have the overheat warning, you can
drive. Just to be safe, drive slower for about
10 minutes.
If the warning doesn’t come back on, you can drive
normally.
If the warning continues and you have not stopped,
pull over, stop, and park your vehicle right away.
If there’s still no sign of steam, you can push down the
accelerator until the engine speed is about twice as
fast as normal idle speed for at least three minutes while
you’re parked. If you still have the warning’turn
off the
engine and get everyone
out of the vehicle until it cools
down.
You may decide not to lift the hood but to get service
help right away.
2. Turn on your heater to full hot at the highest fan
speed and open the window as necessary.
5-32

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
filler neck may be lower.
If the level is lower, add
more of the proper
DEX-COOL@ coolant mixture
through the filler neck until the level reaches
the base of the filler neck.
Then replace the pressure cap. At any time during
this procedure
if coolant begins to flow out of
the filler 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.
5-39

FuseKircuit Usage
Breaker
1
2
Stop/Turn/Hazard Lamps,
Center High Mounted Stop Lamp,
Anti-Lock Brakes
Radio Accy, Rear Seat
Audio Controls
FuseKircuit
Breaker
3
4
5
6
8
9
Usage
Courtesy Lamps, Glove Box Lamp,
Dome Reading Lamps, Vanity Mirror
Lamps, Courtesy Lamps
Daytime Running Lamps Relay,
Instrument Panel Cluster
Rear Defogger
Cruise Module, Truck Body Control Module, Instrument Panel Cluster,
Cruise Control Switch,
Electrochromic Mirror
Power Outlets, DLC,
Subwoofer Amplifier
Crank Circuit Fuse, ParWNeutral
Switch, Starter Enabler Relay
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
5-94

13
14
15
16
Fuse/Circuit Usage Breaker
10 Air Bag System
11 Not Used
12 L, MI, M2 Blower Motor, Rear Air
Conditioning Relay Coil, Front Cont.
Temp. Door Motor, HI Blower Relay.
Defogger Timer Coil
Cigarette Lighter, Door Lock
Switches, Dutch Door Release Module
Cluster Illum, Climate Controls,
Chime Module, Radio Illumination,
Rear Heat Switch Illumination, Rear
Wipermasher Switch Illumination,
Rear Liftgate Switch Illumination,
Remote Cassette Illumination,
Overhead Console, Truck Body
Control Illurnination
Truck Body Module, Headlamp Relay
Front Turn Signals, Rear Turn
Signals, Trailer Turn Signals,
Back-up Lamps, Brake Transmission
Shift Interlock Solenoid 21
22
23
24
A
19
20
FuseKircuit
Usage
Breaker
17 Front Wipers, Front Washer Pump
18 VCM-lgn
3, VCM-Brake, Cruise
Stepper Motor Signal, ATC Module
Instrument Panel Radio: ATC
(Main Feed),
2000 Series (Standby)
PRNDUOdometer, TCC Enable and
PWM Solenoid, Shift A and Shift B
Solenoids, 3-2 Downshift Solenoid, Instrument Panel Cluster, VCM
Module
Powr Adjust Mirrors
Not Used
Rear Wiper, Rear Washer Pump
Not Used
(Circuit Breaker) Power Door Lock
Relay, 6-Way Power Seats
(Circuit Breaker) Power Windows
B
5-95

Usage
Rear/Heat and Air Conditioning
Relays
AIC Relay
(Rear Heat
and AIC)
Relay
Relay
A/C Enable
Relay
Upfitter-ACCY
Upfitter Accessory
Starter Enable Starter
Headlamps Relay
Fuel Pump
Relay Air
Conditioning
Headlamps
Fuel Pump
FuselCircuit
Usage
UPFITTER- Upfitter Battery Power Stud,
BATT Trailer Wiring Harness
UPFITTER- Upfitter Accessory Relay
ACCY
Spare Not used
Spare Not used
Breaker FuselCircuit
Breaker
Spare
ECM-1 B
HORN
AIC COMP
RR HTR/AC ATC
FRT HVAC
ENG-I
IGN-E
ECM-I
Blank
RH HDLMP
LH Headlamp
Blank
Blank
Usage
Not used
Fuel Pump Relay and Motor, VCM,
Oil Pressure Switch/Sender
Horn Relay and Horn
Air Conditioning Enable Relay and
Compressor
Rear Heater and Air Conditioning
Active Transfer Case-L Van
Front Heater and Air Conditioning
Oxygen Sensors, Camshaft Position
Sensor, Mass Air Flow Sensor,
Evaporative Emission Canister
Vent Solenoid
Air Conditioning Enable Relay Coil
Fuel Injectors
1-6, Crankshaft
Position Sensot, VCM, Coil Driver
Module (EST), Ignition Coil
Not Used
Right Headlamp
Left Headlamp
Not Used
Not Used
5-97

Selecting the Right Schedule
First you’ll need to decide which of the two schedules
is right for your vehicle. Here’s how to decide which
schedule to follow:
Short Trip/City Definition
Follow the Short Trip/City Scheduled Maintenance if any
one of these conditions is true for your vehicle:
e
e
e
e
Most trips are less than 5 miles (8 km). This is
particularly important when outside temperatures
are below freezing.
Most trips include extensive idling (such as frequent
driving in stop-and-go traffic).
You frequently tow a trailer or use a carrier on top
of your vehicle.
If the vehicle is used for delivery service, police,
taxi or other commercial application.
One of the reasons you should follow this schedule if
you operate your vehicle under any of these conditions
is that these conditions cause engine oil to break
down sooner.
Short Trip/City Intervals
Every 3,000 Miles (5 000 km): Engine Oil and Filter
Change (or
3 months, whichever occurs first). Chassis
Lubrication (or
3 months, whichever occurs first).
Drive Axle Fluid Check.
Every 6,000 Miles (IO 000 km): Tire Rotation.
Every 15,000 Miles (25 000 km): Engine Air
Cleaner Filter Inspection,
if driving in dusty conditions.
Front Wheel Bearing Repack (two-wheel drive only)
(or at each brake relining, whichever occurs first).
Automatic Transmission Service (severe conditions only).
Every 30,000 Miles (50 000 km): Engine Air Cleaner
Filter Replacement. Fuel Filter Replacement.
Every 50,000 Miles (83 000 km): Automatic
Transmission Service (normal conditions).
Transfer Case Fluid Change.
Every 100,000 Miles (166 000 km): Spark Plug Wire
Inspection. Spark Plug Replacement. Positive
Crankcase Ventilation (PCV) Valve Inspection.
Every 150,000 Miles (240 000 km): Cooling System
Service (or every
60 months, whichever occurs
first). Engine Accessory Drive Belt Inspection.
These intervals only summarize maintenance services.
Be sure to follow the complete scheduled maintenance
on the following pages.
6-5

Long Trip/Highway Definition
Follow this scheduled maintenance only if none of
the conditions from the Short Trip/City Scheduled
Maintenance are true. Do not use this schedule
if the
vehicle is used for trailer towing, driven in a dusty area
or used
off paved roads. Use the Short Trip/City
schedule for these conditions.
Driving a vehicle with a fully warmed engine under
highway conditions will cause engine oil
to break
down slower.
Long Trip/Highway Intervals
Every 7,500 Miles (12 500 km): Engine Oil and Filter
Change (or every
12 months, whichever occurs first).
Chassis Lubrication (or
12 months, whichever
occurs first). Drive Axle Fluid Check. Tire Rotation.
Every 15,000 Miles (25 000 km): Automatic
Transmission Service (severe conditions only).
Every 30,000 Miles (50 000 km): Fuel Filter
Replacement. Engine Air Cleaner Filter Replacement.
Front Wheel Bearing Repack (two-wheel drive only)
(or at each brake relining, whichever occurs first).
Every 50,000 Miles (83 000 km): Automatic
Transmission Service (normal conditions).
Transfer Case Fluid Change.
Every 100,000 Miles (166 000 km): Spark Plug Wire
Inspection. Spark Plug Replacement. Positive
Crankcase Ventilation (PCV) Valve Inspection.
Every 150,000 Miles (240 000 km): Cooling System
Service (or every
60 months, whichever occurs first).
Engine Accessory Drive Belt Inspection.
These intervals only summarize maintenance services.
Be sure to follow the complete scheduled maintenance
on the following pages.
6-6