ignition CHEVROLET ASTRO 2004 Service Manual

Press the button on the end of the shift lever to turn
tow/haul mode on and off. While activated, the indicator
light on the instrument panel will be on. Tow/haul
mode will turn off automatically when the ignition is
turned off. See
Tow/Haul Mode Light on page 3-36.
Tow/haul is most effective when the vehicle and trailer
combined weight is at least 75% of the vehicle's
Gross Combined Weight Rating (GCWR). See ªWeight
of the Trailerº later in this section.
Driving with tow/haul activated without a heavy load will
cause reduced fuel economy and unpleasant engine
and transmission driving characteristics, but will
not cause damage.
Weight of the Trailer
How heavy can a trailer safely be?
It depends on how you plan to use your rig. For
example, speed, altitude, road grades, outside
temperature and how much your vehicle is used to pull
a trailer are all important. And, it can also depend
on any special equipment that you have on your vehicle.
The following chart shows how much your trailer can
weigh, based upon your vehicle model and options.
Vehicle Axle RatioMax. Trailer Wt. (lbs)
(kg) GCWR (lbs) (kg)
Two-Wheel Drive (Cargo)3.42
3.735,200 (2359)
5,700 (2585)9,500 (4309)
10,000 (4536)
Two-Wheel Drive (Passenger)3.42
3.734,900 (2223)
5,400 (2449)9,500 (4309)
10,000 (4536)
All-Wheel Drive (Cargo)3.42
3.735,000 (2268)
5,500 (2495)9,500 (4309)
10,000 (4536)
All-Wheel Drive (Passenger)3.42
3.734,600 (2087)
5,100 (2313)9,500 (4309)
10,000 (4536)
4-37

Jump Starting
If your battery has run down, you may want to use
another vehicle and some jumper cables to start your
vehicle. But please follow the numbered steps to
do it safely.
{CAUTION:
Batteries can hurt you. They can be dangerous
because:
·They contain acid that can burn you.
·They contain gas that can explode or
ignite.
·They contain enough electricity to
burn you.
If you do not follow these steps exactly, some
or all of these things can hurt you.
Notice:Ignoring these steps could result in costly
damage to your vehicle that would not be covered
by your warranty.
Trying to start your vehicle by pushing or pulling it
will not work, and it could damage your vehicle.
1. Check the other vehicle. It must have a
12±-volt battery with a negative ground system.
Notice:If the other vehicle's system is not a 12-volt
system with a negative ground, both vehicles can
be damaged. Only use vehicles with 12-volt systems
with negative grounds to jump start your vehicle.
2. Get the vehicles close enough so the jumper cables
can reach, but be sure the vehicles aren't touching
each other. If they are, it could cause a ground
connection you don't want. You wouldn't be able to
start your vehicle, and the bad grounding could
damage the electrical systems.
To avoid the possibility of the vehicles rolling, set
the parking brake ®rmly on both vehicles involved in
the jump start procedure. Put an automatic
transmission in PARK (P) and a manual
transmission in NEUTRAL.
3. Turn off the ignition on both vehicles. Unplug
unnecessary accessories plugged into the cigarette
lighter or accessory power outlets. Turn off all
lamps that aren't needed as well as radios. This will
avoid sparks and help save both batteries. In
addition, it could save your radio!
5-43

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

Ignition Transmission Lock Check
While parked, and with the parking brake set, try to turn
the ignition key to LOCK in each shift lever position.
·The key should turn to LOCK only when the
shift lever is in PARK (P).
·The key should come out only in LOCK.
Parking Brake and Automatic
Transmission Park (P) Mechanism
Check
{CAUTION:
When you are doing this check, your vehicle
could begin to move. You or others could be
injured and property could be damaged. Make
sure there is room in front of your vehicle in
case it begins to roll. Be ready to apply the
regular brake at once should the vehicle begin
to move.Park on a fairly steep hill, with the vehicle facing
downhill. Keeping your foot on the regular brake, set the
parking brake.
·To check the parking brake's holding ability: With
the engine running and transmission in
NEUTRAL (N), slowly remove foot pressure from
the regular brake pedal. Do this until the vehicle is
held by the parking brake only.
·To check the PARK (P) mechanism's holding ability:
With the engine running, shift to PARK (P). Then
release the parking brake followed by the regular
brake.
Underbody Flushing Service
At least every spring, use plain water to ¯ush any
corrosive materials from the underbody. Take care to
clean thoroughly any areas where mud and other debris
can collect.
6-27

H
Hatch Release................................................2-13
Hazard Warning Flashers................................... 3-4
Head Restraints............................................... 1-5
Headlamp High/Low-Beam Changer.................... 3-7
Headlamp Wiring............................................5-96
Headlamps....................................................5-50
Bulb Replacement.......................................5-49
Front Turn Signal Lamps..............................5-53
Halogen Bulbs............................................5-49
Highway Hypnosis...........................................4-22
Hill and Mountain Roads..................................4-22
Hitches..........................................................4-39
HomeLink
žTransmitter, Programming................2-31
Hood
Checking Things Under.................................. 5-9
Release.....................................................5-10
Horn............................................................... 3-5
How to Add Coolant to the Coolant
Recovery Tank............................................5-32
How to Add Coolant to the Radiator..................5-34
How to Add Fluid............................................5-25
How to Check........................................5-23, 5-67
How to Check Lubricant...................................5-48
How to Check Power Steering Fluid..................5-37How to Inspect the Engine Air
Cleaner/Filter..............................................5-22
How to Use This Manual...................................... ii
How to Wear Safety Belts Properly...................1-18
Hydroplaning..................................................4-18
I
If No Steam Is Coming From Your Engine..........5-29
If Steam Is Coming From Your Engine...............5-28
If the Light Is Flashing.....................................3-32
If the Light Is On Steady.................................3-32
If You Are Caught in a Blizzard.........................4-26
If You Are Stuck in Sand, Mud, Ice or Snow.......4-28
If You Do Decide To Pull A Trailer.....................4-36
Ignition Positions.............................................2-17
Ignition Transmission Lock Check......................6-27
Infants and Young Children, Restraints...............1-38
In¯ation - Tire Pressure...................................5-66
Inspection
Brake System.............................................6-29
Engine Cooling System................................6-28
Exhaust System..........................................6-28
Fuel System...............................................6-28
Part C - Periodic Maintenance.......................6-28
Steering, Suspension and Front Drive Axle
Boot and Seal.........................................6-28
7