ignition CHEVROLET EXPRESS 2004 Service Manual

Care of Your CDs
Handle CDs carefully. Store them in their original cases
or other protective cases and away from direct
sunlight and dust. If the surface of a CD is soiled,
dampen a clean, soft cloth in a mild, neutral detergent
solution and clean it, wiping from the center to the edge.
Be sure never to touch the side without writing when
handling CDs. Pick up CDs by grasping the outer edges
or the edge of the hole and the outer edge.
Care of Your CD Player
The use of CD lens cleaners for CD players is not
advised, due to the risk of contaminating the lens of the
CD optics with lubricants internal to the CD mechanism.
Fixed Mast Antenna
The xed mast antenna can withstand most car washes
without being damaged. If the mast should ever
become slightly bent, straighten it out by hand. If the
mast is badly bent, replace it.
Check occasionally to make sure the mast is still
tightened to the fender. If tightening is required, tighten
by hand, then with a wrench one quarter turn.
Chime Level Adjustment
The radio is the vehicle chime producer. The chime is
produced from the driver’s side front door speakers.
To change the volume level, press and hold
pushbutton 6 with the ignition on and the radio power
off. The chime volume level will change from the normal
level to loud, and LOUD will appear on the radio
display. To change back to the default or normal setting,
press and hold pushbutton 6 again. The chime level
will change from the loud level to normal, and NORMAL
will appear on the radio display. Each time the chime
volume is changed, three chimes will sound to indicate
the change. Removing the radio and not replacing it
with a factory radio or chime module will disable
vehicle chimes.
3-74

{CAUTION:
Coasting downhill in NEUTRAL (N) or with the
ignition off is dangerous. Your brakes will have
to do all the work of slowing down. They could
get so hot that they would not work well. You
would then have poor braking or even none
going down a hill. You could crash. Always
have your engine running and your vehicle in
gear when you go downhill.
Know how to go uphill. You may want to shift down
to a lower gear. The lower gears help cool your
engine and transmission, and you can climb the
hill better.
Stay in your own lane when driving on two-lane
roads in hills or mountains. Do not swing wide
or cut across the center of the road. Drive at speeds
that let you stay in your own lane.
As you go over the top of a hill, be alert. There
could be something in your lane, like a stalled car or
an accident.
You may see highway signs on mountains that
warn of special problems. Examples are long
grades, passing or no-passing zones, a falling rocks
area, or winding roads. Be alert to these and take
appropriate action.
4-23

Tow/Haul Mode
Tow/haul is designed to assist while your vehicle is
pulling a large or heavy load or trailer. Tow/haul is most
useful while pulling such a load in rolling terrain, in
stop-and-go traffic, or when you need improved
low-speed control, such as when parking. The purpose
of the tow/haul mode is to:
Reduce the frequency and improve the predictability
of transmission shifts,
provide the same solid shift feel when pulling a
heavy load as when the vehicle is unloaded,
improve control of vehicle speed while requiring
less throttle pedal activity.
Press this button located
to the right of the steering
wheel on the instrument
panel 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. SeeTow/Haul Mode Light
on page 3-38.
Tow/haul is most effective when the vehicle and trailer
combined weight is at least 75 percent of the vehicle’s
Gross Combined Weight Rating (GCWR). See “Weight
of the Trailer” 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.
4-36

To reset the change engine oil light, do the following:
1. Turn the ignition key to RUN with the engine off.
2. Fully press and release the accelerator pedal slowly
three times within ve seconds.
3. If the Change Engine Oil light ashes for
ve seconds, the system is reset.
4. Turn the key to LOCK.
If the change engine oil light comes back on when you
start your vehicle, the engine oil life system has not
reset. Repeat the procedure. If it still does not reset, see
your dealer for service. SeeChange Engine Oil Light
on page 3-35.
What to Do with Used Oil
Used engine oil contains certain elements that may be
unhealthy for your skin and could even cause cancer.
Do not let used oil stay on your skin for very long. Clean
your skin and nails with soap and water, or a good
hand cleaner. Wash or properly dispose of clothing or
rags containing used engine oil. See the manufacturer’s
warnings about the use and disposal of oil products.
Used oil can be a threat to the environment. If you
change your own oil, be sure to drain all the oil from the
lter before disposal. Never dispose of oil by putting it inthe trash, pouring it on the ground, into sewers, or into
streams or bodies of water. Instead, recycle it by taking it
to a place that collects used oil. If you have a problem
properly disposing of your used oil, ask your dealer, a
service station or a local recycling center for help.
Engine Air Cleaner/Filter
The engine air cleaner/lter is located near the center of
the engine compartment. SeeEngine Compartment
Overview on page 5-12for more information on location.
5-17

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 are not touching
each other. If they are, it could cause a ground
connection you do not want. You would not 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) or a manual transmission
in NEUTRAL before setting the parking brake.
Notice:If you leave your radio or other accessories
on during the jump starting procedure, they could
be damaged. The repairs would not be covered
by your warranty. Always turn off your radio and
other accessories when jump starting your vehicle.
3. Turn off the ignition on both vehicles. Unplug
unnecessary accessories plugged into the cigarette
lighter or the accessory power outlet. Turn off
the radio and all lamps that are not needed. This
will avoid sparks and help save both batteries. And
it could save the radio!
5-39

Fuse Usage
6 Ignition 0
7 Stoplamp
8 Right Rear Defogger/Heated Mirror
9Right Daytime Running
Lamp/Turn Signal
10Left Daytime Running
Lamp/Turn Signal
11 Truck Body Control Module 4
12 Fuel Pump
13 Trailer
14 Flasher
15 Horn
16 Truck Body Control Module 3
17 Trailer Stop/Turn Signal
18 Truck Body Control Module 2
19 Truck Body Control Module
20 Remote Function Actuator
21 Engine 2Fuse Usage
22 Ignition E
23 Engine 1
24Truck Body Control Module
Ignition 1
25 Spare
26 RPA/Inside Rearview Mirror
27 Crankcase
28Brake Transmission Shift
Interlock System
29 Auxiliary Power Outlets
30 Cigarette Lighter
31 Instrument Panel Cluster
32 Air Conditioning
33 Spare
34 Vent
35 Spare
36 Vehicle Back Up
37Supplemental Inatable
Restraint System
5-95

Fuse Usage
38 Powertrain Control Module Ignition 1
39 Oxygen Sensor B
40 Oxygen Sensor A
41 Windshield Wipers
42 Right Headlamp - Low Beam
43 Left Headlamp - Low Beam
44 Left Headlamp - High Beam
45 Right Headlamp - High Beam
46Truck Body Control
Module-Accessory
47 Front Windshield Wiper
48 Anti-Lock Brakes
49 Ignition A
50 Trailer
51 Climate Control Blower
52 Ignition B
63 Spare
64 SpareFuse Usage
Relays Usage
53 Windshield Wiper
54 Air Conditioning
55 Spare
56 Headlamp - High Beam
57 Fuel Pump
58 Headlamp - Low Beam
59 Horn
61 Starter
62 Spare
Circuit Breaker Usage
60 Power Seat
5-96

At Least Once a Year
Starter Switch Check
{CAUTION:
When you are doing this inspection, the
vehicle could move suddenly. If the vehicle
moves, you or others could be injured.
1. Before you start, be sure you have enough room
around the vehicle.
2. Firmly apply both the parking brake and the
regular brake. SeeParking Brake on page 2-24
if necessary.
Do not use the accelerator pedal, and be ready to
turn off the engine immediately if it starts.
3. Try to start the engine in each gear. The starter
should work only in PARK (P) or NEUTRAL (N).
If the starter works in any other position, contact
your GM Goodwrench dealer for service.
Automatic Transmission Shift Lock
Control System Check
{CAUTION:
When you are doing this inspection, the
vehicle could move suddenly. If the vehicle
moves, you or others could be injured.
1. Before you start, be sure you have enough
room around the vehicle. It should be parked
on a level surface.
2. Firmly apply the parking brake. SeeParking Brake
on page 2-24if necessary.
Be ready to apply the regular brake immediately if
the vehicle begins to move.
3. With the engine off, turn the ignition to RUN, but do
not start the engine. Without applying the regular
brake, try to move the shift lever out of PARK (P)
with normal effort. If the shift lever moves out
of PARK (P), contact your GM Goodwrench dealer
for service.
6-11

Ignition Transmission Lock Check
While parked, and with the parking brake set, try to turn
the ignition to LOCK in each shift lever position.
The ignition should turn to LOCK only when the
shift lever is in PARK (P).
The key should come out only in LOCK.
Contact your GM Goodwrench dealer if service
is required.
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.
Contact your GM Goodwrench dealer if service
is required.
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.
6-12

Headlamps (cont.)
Front Turn Signal, Sidemarker and
Parking Lamps.........................................5-48
Halogen Bulbs............................................5-47
High/Low Beam Changer................................ 3-8
On Reminder..............................................3-14
Heater...........................................................3-18
Highbeam On Light.........................................3-37
Highway Hypnosis...........................................4-21
Hill and Mountain Roads..................................4-22
Hood
Checking Things Under................................5-10
Release.....................................................5-11
Horn............................................................... 3-6
How to Use This Manual...................................... ii
How to Wear Safety Belts Properly...................1-15
I
Ignition Positions.............................................2-19
Infants and Young Children, Restraints...............1-33
Ination -- Tire Pressure..................................5-58
Instrument Panel
Brightness..................................................3-15
Cluster.......................................................3-23
Overview..................................................... 3-4
J
Jump Starting.................................................5-38
K
Keyless Entry System....................................... 2-3
Keys............................................................... 2-2
L
Labelling, Tire Sidewall....................................5-53
Lamps
Battery Run-Down Protection.........................3-16
Dome........................................................3-15
Dome Lamp Override...................................3-15
Exterior......................................................3-13
Reading.....................................................3-16
LATCH System
Child Restraints...........................................1-49
Securing a Child Restraint Designed for
the LATCH System...................................1-51
Light
Airbag Off..................................................3-26
Airbag Readiness........................................3-25
Anti-Lock Brake System Warning...................3-30
6