trailer CHEVROLET EXPRESS 2006 Owner's Guide

Trailer Wiring Harness
The optional heavy-duty trailer wiring package includes
a wiring harness, with a seven-pin connector at the
rear of the vehicle and a four-wire harness assembly
under the driver side of the instrument panel. The
four-wire harness assembly comes without a connector.
If the vehicle does not have a trailer hitch, the
seven-wire harness assembly with connector is taped
together and located in a frame pocket at the driver side
rear left corner of the frame.
If the vehicle has a trailer hitch, the seven-wire harness
assembly with connector is attached to a bracket on
the hitch platform. In both cases, the seven-wire harness
has a connector and includes a 30-amp feed wire.
The seven-wire harness connector contains the following
trailer circuits:
•Light Green: Back-up Lamps (10A fuse)**
•White: Ground
•Dark Blue: Trailer Brake Signal
•Dark Green: Right Rear Stop and Turn Signal*
•Red/Black Stripe: Battery Feed (30A Fuse)
•Brown: Trailer Park Lamp Supply Voltage
(15A fuse)**
•Yellow: Left Rear Stop and Turn Signal *
The four-wire harness (without connector) contains the
following circuits:
•Black: Ground
•Red/White: Battery Feed
•Dark Blue: Trailer Brake Signal
•Light Blue: CHMSL/Stoplamp Supply Voltage
* If the vehicle is a cutaway with trailer provisions, a
15 amp fuse will be shared for both left/stop trailer turn
and right/stop trailer turn signals. However, the
cutaway lighting connector will have a 10 amp fuse for
each signal.
** If the vehicle is a cutaway with trailer provisions, a
15 amp fuse will be shared for trailer park lamps
and cutaway rear lighting connector park lamps. Also, a
10 amp fuse will be shared for trailer back-up lamps
and cutaway rear lighting connector back-up lamps.
5-42

How to Check Automatic Transmission
Fluid
Because this operation can be a little difficult, you may
choose to have this done at the dealer/retailer 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.
Notice:Too much or too little uid can damage
your transmission. Too much can mean that some
of the uid could come out and fall on hot engine
parts or exhaust system parts, starting a re.
Too little uid could cause the transmission to
overheat. Be sure to get an accurate reading if you
check your transmission uid.
Wait at least 30 minutes before checking the
transmission fluid level if you have been driving:
•When outside temperatures are above 32°C (90°F).
•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 82°C to 93°C
(180°F to 200°F).
Get the vehicle warmed up by driving about 24 km
(15 miles) when outside temperatures are above 10°C
(50°F). If it is colder than 10°C (50°F), drive the vehicle in
D (DRIVE) until the engine temperature gage moves and
then remains steady for 10 minutes.
A cold fluid check can be made after the vehicle has been
sitting for eight hours or more with the engine off, but this
is used only as a reference. Let the engine run at idle for
five minutes if outside temperatures are 50°F (10°C) or
more. If it is colder than 10°C (50°F), you may have to
idle the engine longer. Should the fluid level be low during
this cold check, you must check the fluid hot before
adding fluid. Checking the fluid hot will give you a more
accurate reading of the fluid level.
6-22

How to Check Automatic Transmission
Fluid
Because this operation can be difficult, it is recommended
to have this check done at the dealer/retailer service
department, which can monitor the transmission
temperature. The transmission fluid level increases
with temperature. To obtain a highly accurate fluid level
check, the transmission temperature must be measured.
If it is decided to check the fluid level, be sure to follow
all the instructions here, or a false reading on the
dipstick may occur.
Notice:Too much or too little uid can damage
your transmission. Too much can mean that some
of the uid could come out and fall on hot engine
parts or exhaust system parts, starting a re.
Too little uid could cause the transmission to
overheat. Be sure to get an accurate reading if you
check your transmission uid.
Wait at least 30 minutes with the engine Off, before
checking the transmission fluid level if the vehicle has
been driven:
•In hot weather, when outside temperatures are
above 32°C (90°F).
•The vehicle is heavily loaded.
•At high speed for quite a while in hot weather.
•In heavy traffic and hot weather.
•While pulling a trailer.
After driving under these conditions, a hot check can
be performed. The fluid should be Hot, which is
71°C to 93°C (160°F to 200°F).
A cold fluid level check can be performed after the vehicle
has been sitting for eight hours or more with the engine
Off, but this is used only as a reference. Let the engine
run at idle for five minutes if outside temperatures is
between 15°C to 32°C (60°F to 90°F). Should the fluid
level be low during this cold check, the fluid must be
checked Warm or Hot before adding fluid. If the outside
temperature is colder than 15°C (60°F) or hotter than
32°C (90°F), a cold check cannot be performed.
A warm fluid level check can be performed by driving
the vehicle under lightly loaded conditions and outside
temperatures between 10°C to 27°C (50°F to 80°F).
The vehicle should be driven for at least 15 miles before
performing a warm check. Checking the fluid Warm or
Hot will give a more accurate reading of the fluid level
than a cold check.
Because the vehicle is equipped with a high-efficiency
air-to-oil cooler, the transmission fluid temperature
may not reach the required Hot fluid level checking
temperature under normal lightly loaded driving vehicle
conditions.
6-25

If Steam Is Coming From The Engine
Compartment
{WARNING:
Steam from an overheated engine can burn you
badly, even if you just open the hood. Stay away
from the engine if you see or hear steam coming
from it. Just turn it off and get everyone away from
the vehicle until it cools down. Wait until there
is no sign of steam or coolant before you open
the hood.
If you keep driving when your engine is
overheated, the liquids in it can catch fire. You or
others could be badly burned. Stop your engine if
it overheats, and get out of the vehicle until the
engine is cool.
If No Steam Is Coming From The
Engine Compartment
If an engine overheat warning is displayed but no steam
can be seen or heard, the problem may not be too
serious. Sometimes the engine can get a little too
hot when the vehicle:
•Climbs a long hill on a hot day.
•Stops after high-speed driving.
•Idles for long periods in traffic.
•Tows a trailer. See “Driving on Grades” under
Towing a Trailer on page 5-30.
If the overheat warning is displayed with no sign of
steam:
1. Turn the air off.
2. Turn the heater on to the highest temperature and
to the highest fan speed. Open the windows as
necessary.
3. In heavy traffic, let the engine idle in N (Neutral)
while stopped. If it is safe to do so, pull off the
road, shift to P (Park) or N (Neutral) and let
the engine idle.
6-36

If the temperature overheat gage is no longer in the
overheat zone or an overheat warning no longer
displays, the vehicle can be driven. Continue to drive
the vehicle slow for about 10 minutes. Keep a safe
vehicle distance from the car in front of you. If the
warning does not come back on, continue to drive
normally.
If the warning continues, pull over, stop, and park the
vehicle right away.
If there is still no sign of steam, push down the
accelerator until the engine speed is about twice
as fast as normal idle speed for at least three minutes
while you are parked. If you still have the warning,
turn off the engine until it cools down.
You may decide not to lift the hood but to get service
help right away.Engine Fan Noise
Your 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 fan is spinning slower and 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
as the clutch more fully 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 partially disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch partially
disengages.
6-37

Floor Console Fuse Block
The floor console fuse block is located under the
driver seat.
Mini-Fuse Usage
F1 Empty
F2 Steering Wheel Sensor
F3 Auxiliary Parking Lamps (Cut-Away)
F4 Front Park Lamps
F5 Trailer Park Lamps
F6 Upfitter Park Lamps
F7 Right Rear Park Lamp
F8 Left Rear Park Lamp
F9 Outside Rear View Mirror Switch
F10 Airbag/AOS
F11 Empty
F12 Empty
F13Heating, Ventilation and
Air Conditioning 2
F14Heating, Ventilation and
Air Conditioning 1
F15 Empty
F17 Outside Rear View Mirror Heater
F18 Rear Window Defogger
F19 Compass
F20 Radio/Chime
F21Remote Function Actuator/
Tire Pressure Monitor
6-111

Mini-Fuse Usage
F22Ignition Switch/Discrete Logic
Ignition Sensor (PK3)
F23 Instrument Panel Cluster
F25Heating, Ventilation and
Air Conditioning Control
F26 Auxiliary/Trailer Backup
F27 Tail Lamps Backup
F30 Upfitter Courtesy Lamps
F31 Front Door Lock
F32 Rear Door Lock
F33 Cargo Door Unlock
F34 Passenger Door Unlock
F35 Rear Passenger Door Unlock
F36 Driver Door Unlock
F37 Empty
F38 Empty
J-Case Fuse Usage
F16 Upfitter Auxiliary 1
F24 Empty
F28 Upfitter Auxiliary 2 Reading Lamps
F29 Rear Blower
Relays Usage
K1 Run (High Current Micro)
K2 Empty (High Current Micro)
K3 Park Lamps (High Current Micro)
K4Upfitter Auxiliary 2
(High Current Mini)
K5 Rear Defogger (High Current Micro)
K6Retained Accessory Power (RAP)
(High Current Micro)
Circuit Breaker Usage
CB1 Power Seats
CB2 Power Windows
Engine Compartment Fuse Block
The fuse block is located in the engine compartment on
the driver side of the vehicle.
Notice:Spilling liquid on any electrical components
on the vehicle may damage it. Always keep the
covers on any electrical component.
6-112

Mini Fuse Usage
3 Right Stop/Turn Trailer
4 Spare
5 Spare
6 Fuel System Control Module Ignition
7 Body Control Module 5
8 Body Control Module 7
9 Body Control Module 4
10 Instrument Panel Cluster
11 Trailer Wiring
12 Spare
13 Brake Switch
14 Windshield Washer
16 Horn
17 Transmission
18 Air Conditioning Compressor
19 Engine Control Module Battery
20 Spare
21 Left Stop/Turn Trailer
22 Spare
23 Spare
24 Fuel Pump
25 Auxiliary Power Outlet
26 Body Control Module 3
6-113

J-Case Fuse Usage
1 ABS Motor
2 ABS Module
41 Spare
42 Trailer Wiring
43 Fan High
44 Starter Solenoid
45 Engine Control Module/Powertrain
46 Fuel System Control Module Battery
47 Fan Lo
74 Front BlowerRelay Usage
15 Run/Crank
37 Spare
38 Fuel Pump
39 Crank
40 Air Conditioning Compressor
48 Fan High
49 Powertrain
50 Fan Clutch (EV)
57 Fan Low
60 Fan Control
6-115

•Exhaust system and nearby heat shields inspection
for loose or damaged components.
•Throttle system inspection for interference, binding
or for damaged or missing parts. Replace parts
as needed. Replace any components that have
high effort or excessive wear. Do not lubricate
accelerator or cruise control cables.
First Engine Oil Change After Every
40 000 km/25,000 Miles
•
Fuel system inspection for damage or leaks.
First Engine Oil Change After Every
80 000 km/50,000 Miles
•
Engine air cleaner filter replacement. SeeEngine
Air Cleaner/Filter on page 6-20.
•Automatic transmission fluid change (severe
service) for vehicles mainly driven in heavy
city traffic in hot weather, in hilly or mountainous
terrain, when frequently towing a trailer, or used
for taxi, police, or delivery service. SeeAutomatic
Transmission Fluid (4-Speed Transmission) on
page 6-21orAutomatic Transmission Fluid
(6-Speed Transmission) on page 6-24.
•All-wheel drive only: Transfer case fluid change
(severe service) for vehicles mainly driven when
frequently towing a trailer, or used for taxi, police, or
delivery service. Check vent hose at transfer case for
kinks and proper installation. Check to be sure vent
hose is unobstructed, clear, and free of debris.
During any maintenance, if a power washer is used
to clean mud and dirt from the underbody, care
should be taken to not directly spray the transfer
case output seals. High pressure water can
overcome the seals and contaminate the transfer
case fluid. Contaminated fluid will decrease the life
of the transfer case and should be replaced.
•Evaporative control system inspection. Check all
fuel and vapor lines and hoses for proper hook-up,
routing, and condition. Check that the purge valve, if
the vehicle has one, works properly. Replace as
needed.An Emission Control Service. The U.S.
Environmental Protection Agency or the California
Air Resources Board has determined that the failure
to perform this maintenance item will not nullify the
emission warranty or limit recall liability prior to the
completion of the vehicle’s useful life. We, however,
urge that all recommended maintenance services
be performed at the indicated intervals and the
maintenance be recorded.
7-7