wiring CHEVROLET EXPRESS 2023 Owners Manual

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
16547501) - 2023 - CRC - 6/10/22
44 Seats and Restraints
Servicing the Airbag-Equipped
Vehicle
Airbags affect how the vehicle should be
serviced. There are parts of the airbag
system in several places around the vehicle.
Your dealer and the service manual have
information about servicing the vehicle and
the airbag system. To purchase a service
manual, seePublication Ordering
Information 0260.
{Warning
For up to 10 seconds after the vehicle is
turned off and the battery is
disconnected, an airbag can still inflate
during improper service. You can be
injured if you are close to an airbag
when it inflates. Avoid yellow connectors.
They are probably part of the airbag
system. Be sure to follow proper service
procedures, and make sure the person
performing work for you is qualified to
do so.
Adding Equipment to the
Airbag-Equipped Vehicle
Adding accessories that change the vehicle's
frame, bumper system, height, front end,
or side sheet metal may keep the airbag
system from working properly.
The operation of the airbag system can also
be affected by changing, including
improperly repairing or replacing, any parts
of the following:
.Airbag system, including airbag modules,
front or side impact sensors, sensing and
diagnostic module, or airbag wiring
.Front seats, including stitching, seams or
zippers
.Seat belts
.Steering wheel, instrument panel, ceiling
trim, or pillar garnish trim
.Inner door seals, including speakers
Your dealer and the service manual have
information about the location of the airbag
modules and sensors, sensing and diagnostic
module, and airbag wiring along with the
proper replacement procedures.
If the vehicle has rollover roof-rail airbags,
see Different Size Tires and Wheels 0216 for
additional important information. If the vehicle must be modified because you
have a disability and have questions about
whether the modifications will affect the
vehicle's airbag system, or if you have
questions about whether the airbag system
will be affected if the vehicle is modified for
any other reason, call Customer Assistance.
See
Customer Assistance Offices 0254.
Airbag System Check
The airbag system does not need regularly
scheduled maintenance or replacement.
Make sure the airbag readiness light is
working. See Airbag Readiness Light 075.
Caution
If an airbag covering is damaged, opened,
or broken, the airbag may not work
properly. Do not open or break the airbag
coverings. If there are any opened or
broken airbag coverings, have the airbag
covering and/or airbag module replaced.
For the location of the airbags, see Where
Are the Airbags? 037. See your dealer for
service.

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
16547501) - 2023 - CRC - 6/10/22
Instruments and Controls 75
When the engine is not running, but the
ignition is on, this gauge shows the
battery's state of charge in DC volts.
When the engine is running, the gauge
shows the condition of the charging system.
Readings between the low and high warning
zones indicate the normal operating range.
Readings in the low warning zone may occur
when a large number of electrical
accessories are operating in the vehicle and
the engine is left at an idle for an extended
period. This condition is normal since the
charging system is not able to provide full
power at engine idle. As engine speeds are
increased, this condition should correct itself
as higher engine speeds allow the charging
system to create maximum power.
The vehicle can be only driven for a short
time with the reading in either warning
zone. If it must be driven, turn off all
unnecessary accessories.
Readings in either warning zone indicate a
possible problem in the electrical system.
Have the vehicle serviced as soon as
possible.Seat Belt Reminders
Driver Seat Belt Reminder Light
There is a seat belt reminder light on the
instrument cluster.
When the vehicle is started, this light
flashes and a chime may come on to remind
the driver to fasten their seat belt. Then the
light stays on solid until the belt is buckled.
This cycle may continue several times if the
driver remains or becomes unbuckled while
the vehicle is moving.
If the driver seat belt is buckled, neither the
light nor the chime comes on.
Airbag Readiness Light
This light shows if there is an electrical
problem with the airbag system. It is
located in the instrument cluster. The
system check includes the airbag sensor(s),
the airbag on-off switch, the pretensioners
(if equipped), the airbag modules, thewiring, and the crash sensing and diagnostic
module. For more information on the airbag
system, see
Airbag System 035.
The airbag readiness light comes on for
several seconds when the vehicle is started.
If the light does not come on then, have it
fixed immediately.
{Warning
If the airbag readiness light stays on
after the vehicle is started or comes on
while driving, it means the airbag system
might not be working properly. The
airbags in the vehicle might not inflate in
a crash, or they could even inflate
without a crash. To help avoid injury,
have the vehicle serviced right away.
If there is a problem with the airbag
system, a Driver Information Center (DIC)
message may also come on.

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
16547501) - 2023 - CRC - 6/10/22
158 Driving and Operating
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear ofthe chocks.
4. Stop and have someone pick up and store the chocks
Launching and Retrieving a Boat
Backing the Trailer into the Water
{Warning
.Have all passengers get out of the
vehicle before backing onto the sloped
part of the ramp. Lower the driver and
passenger side windows before
backing onto the ramp. This will
provide a means of escape in the
unlikely event the vehicle slides into
the water.
.If the boat launch surface is slippery,
have the driver remain in the vehicle
with the brake pedal applied while the
boat is being launched. The boat
launch can be especially slippery at
low tide when part of the ramp was
previously submerged at high tide. Do
not back onto the ramp to launch the
boat if you are not sure the vehicle
can maintain traction.
(Continued)
Warning (Continued)
.Do not move the vehicle if someone is
in the path of the trailer. Some parts
of the trailer might be underwater and
not visible to people who are assisting
in launching the boat.
Disconnect the wiring to the trailer before
backing the trailer into the water to prevent
damage to the electrical circuits on the
trailer. Reconnect the wiring to the trailer
after removing the trailer from the water.
If the trailer has electric brakes that can
function when the trailer is submerged, it
might help to leave the electrical trailer
connector attached to maintain trailer brake
functionality while on the boat ramp.
To back the trailer into the water: 1. Slowly back down the boat ramp until the boat is floating, but no further than
necessary.
2. Press and hold the brake pedal, but do not shift into P (Park) yet.
3. Have someone place chocks under the front wheels of the vehicle.
4. Gradually release the brake pedal to allow the chocks to absorb the load of
the trailer. 5. Reapply the brake pedal. Then apply the
parking brake and shift into P (Park).
6. Release the brake pedal.
Pulling the Trailer from the Water
To pull the trailer from the water: 1. Press and hold the brake pedal.
2. Start the engine and shift into a gear.
3. Release the parking brake.
4. Let up on the brake pedal.
5. Drive slowly until the tires are clear of the chocks.
6. Stop and have someone pick up and store the chocks.
7. Slowly pull the trailer from the water.
Caution
If the vehicle tires begin to spin and the
vehicle begins to slide toward the water,
remove your foot from the accelerator
pedal and apply the brake pedal. Seek
help to have the vehicle towed up
the ramp.

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
16547501) - 2023 - CRC - 6/10/22
168 Driving and Operating
Tires
.Do not tow a trailer while using a
compact spare tire on the vehicle.
.Tires must be properly inflated to support
loads while towing a trailer. SeeTires
0 203 for instructions on proper tire
inflation.
Safety Chains
Always attach chains between the vehicle
and the trailer, and attach the chains to the
holes on the trailer hitch platform.
Instructions about safety chains may be
provided by the hitch manufacturer or by
the trailer manufacturer.
Cross the safety chains under the tongue of
the trailer to help prevent the tongue from
contacting the road if it becomes separated
from the hitch. Always leave just enough
slack so the combination can turn. Never
allow safety chains to drag on the ground.
Trailer Brakes
Loaded trailers over 675 kg (1,500 lb) must
be equipped with brake systems and with
brakes for each axle. Trailer braking
equipment conforming to Canadian Standards Association (CSA) requirement
CAN3-D313, or its equivalent, is
recommended.
State or local regulations may require the
trailer to have its own braking system if the
loaded weight of the trailer exceeds certain
minimums. These requirements vary from
state to state. Read and follow the
instructions for the trailer brakes so they are
installed, adjusted, and maintained properly.
Never attempt to tap into your vehicle's
hydraulic brake system. If you do, both the
vehicle anti-lock brakes and the trailer
brakes may not function, which could result
in a crash.
Trailer Wiring Harness
Basic Trailer Wiring
If the vehicle is not equipped with a trailer
connector on the rear bumper, a seven-wire
trailering harness is tied to the vehicle’s
frame. The harness requires the installation
of a trailer connector, which is available
through your dealer.
Use only a round, seven-wire connector with
flat blade terminals meeting SAE J2863
specifications for proper electrical
connectivity.The seven-wire harness connector contains
the following trailer circuits:
.Yellow: Stop/Turn Signal Left*
.Dark Green: Stop/Turn Signal Right*
.Brown: Tail/Parking Lamps**
.Light Green: Reverse Lamps**
.Red/Black: Battery Feed
.White: Ground
.Dark Blue: Electric Trailer Brake
* If the vehicle is a cutaway with trailer
provisions, each stop/turn signal has a
15 amp fuse. However, the cutaway lighting
connector will have a 10 amp fuse for each
signal.
**If the vehicle is a cutaway with trailer
provisions, there is a 15 amp fuse for the
trailer park lamps and a 15 amp fuse for the
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.
Heavy-Duty Trailer Wiring Harness Package
lf equipped, the trailer wiring harness, with
a seven-pin connector is mounted on the
trailer hitch.

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
16547501) - 2023 - CRC - 6/10/22
Driving and Operating 169
1. Ground
2. Left Turn/Brake
3. Reverse Lamps
4. Taillamps
5. Battery Feed
6. Right Turn/Brake
7. Electric Brakes
Electric Brake Control Wiring Provisions
If the vehicle is not equipped with an
integrated trailer brake controller, and the
trailer has electric brakes, a trailer brake
controller needs to be installed on the
vehicle. The brake controller should be
installed by your dealer or a qualified
service center.If equipped, wiring provisions for an
aftermarket electric trailer brake controller
are included with the vehicle as part of the
trailer wiring package. The harness contains
the following circuits:
.Dark Blue: Electric Trailer Brakes
.Red/White: Battery Feed
.Lt Blue/White: Brake Apply Signal
.Black: Ground
There are four blunt cut wires under the
floor carpeting in front of the brake pedal.
It will be necessary to have a technician
connect the 12-volt power to the engine
compartment fuse block.
Refer to the aftermarket electric trailer brake
controller owner's manual to determine wire
color coding of the electric trailer brake
controller. The wire colors on the brake
controller may be different from the vehicle.
Trailer Lamps
Always check all trailer lamps are working at
the beginning of each trip, and periodically
on longer trips.
Turn Signals When Towing a Trailer
When properly connected, the trailer turn
signals will illuminate to indicate the vehicle
is turning, changing lanes, or stopping.
When towing a trailer, the arrows on the
instrument cluster will illuminate even if the
trailer is not properly connected or the bulbs
are burned out.
Tow/Haul Mode
Tow/Haul assists when pulling a heavy
trailer or a large or heavy load. For
instructions on how to enter Tow/Haul
mode, see Tow/Haul Mode 0140.
Tow/Haul Mode is designed to be most
effective when the vehicle and trailer
combined weight is at least 75% of the
vehicle's Gross Combined Weight Rating
(GCWR). See “Trailer Weight” underTrailer
Towing 0159.
Tow/Haul Mode is most useful when towing
a heavy trailer or carrying a large or
heavy load:
.Through rolling terrain
.In stop-and-go traffic
.In busy parking lots

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
16547501) - 2023 - CRC - 6/10/22
Vehicle Care 197
4. Reverse Steps 1 and 2 to reinstall thelicense plate bulb assembly.
Electrical System
Electrical System Overload
The vehicle has fuses to protect against an
electrical system overload.
When the current electrical load is too
heavy, the circuit breaker opens and closes,
protecting the circuit until the current load
returns to normal or the problem is fixed.
This greatly reduces the chance of circuit
overload and fire caused by electrical
problems.
Fuses protect the wires that provide the
power to the devices in your vehicle.
If there is a problem on the road and a fuse
needs to be replaced, the same amperage
fuse can be borrowed. Choose some feature
of the vehicle that is not needed to use and
replace it as soon as possible.
To check a fuse, look at the band inside the
fuse. If the band is broken or melted,
replace the fuse. Be sure to replace a bad
fuse with a fuse of the identical size and
rating.
Replacing a Blown Fuse
At the next opportunity, see your dealer to
replace the blown fuse.
Headlamp Wiring
An electrical overload may cause the lamps
to go on and off, or in some cases to
remain off. Have the headlamp wiring
checked right away if the lamps go on and
off or remain off.
Windshield Wipers
If the wiper motor overheats due to heavy
snow or ice, the windshield wipers will stop
until the motor cools and will then restart.
Although the circuit is protected from
electrical overload, overload due to heavy
snow or ice may cause wiper linkage
damage. Always clear ice and heavy snow
from the windshield before using the
windshield wipers.
If the overload is caused by an electrical
problem and not snow or ice, be sure to get
it fixed.

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
16547501) - 2023 - CRC - 6/10/22
198 Vehicle Care
Fuses and Circuit Breakers
The wiring circuits in the vehicle are
protected from short circuits by a
combination of fuses and circuit breakers.
This greatly reduces the chance of damage
caused by electrical problems.
{Danger
Fuses and circuit breakers are marked
with their ampere rating. Do not exceed
the specified amperage rating when
replacing fuses and circuit breakers. Use
of an oversized fuse or circuit breaker can
result in a vehicle fire. You and others
could be seriously injured or killed.
{Warning
Installation or use of fuses that do not
meet GM’s original fuse specifications is
dangerous. The fuses could fail, and result
in a fire. You or others could be injured
or killed, and the vehicle could be
damaged.
See Accessories and Modifications 0173 and
General Information 0173.
To check or replace a blown fuse, see
Electrical System Overload 0197.
Engine Compartment Fuse Block
The fuse block is in the engine compartment
on the driver side of the vehicle.
Vehicles with Upfitter Content
See www.gmupfitter.com for upfitter
provisions and best practices.
Caution
Spilling liquid on any electrical
component on the vehicle may damage
it. Always keep the covers on any
electrical component.

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
16547501) - 2023 - CRC - 6/10/22
Vehicle Care 199
The vehicle may not be equipped with all of
the fuses, relays, and features shown.Fuses Usage
1 ABS Motor Fuses Usage
2 ABS Module Fuses Usage
3 Right Trailer Stoplamp/ Turn Signal Lamp
4 –
5 –
6 Fuel System Control Module/Ignition
7 Body Control Module 5
8 Body Control Module 7
9 Body Control Module 4
10 Instrument Cluster 11 Trailer Wiring
12 –
13 Interior Rear Vision Camera Module
14 Windshield Washer
16 Horn 17 Transmission
18 A/C
19 Engine Control Module Battery

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
16547501) - 2023 - CRC - 6/10/22
200 Vehicle Care
FusesUsage
20 Left Stop/Turn Cutaway Lamp
21 Left Stop/Turn Trailer Lamp
22 Right Stop/Turn Cutaway Lamp
23 –
24 Fuel Pump 25 Auxiliary Power Outlet
26 Body Control Module 3 27 Special Equipment Option
28 Airbag
29 Steering Wheel Sensor
30 Engine Control Module Ignition
31 Transmission Control Module Ignition
32 Transmission Control Module 1 Battery
33 Rear Parking Aid Module Fuses
Usage
34 –
35 –
36 Fuel System Control Module Battery
41 Transmission Control Module 2/Battery Power
42 Trailer Wiring
43 –
44 Starter Solenoid 45 Engine Control Module/ Powertrain Signal 2
46 DC-AC Inverter 47 Fan Low Speed 51 Left High-Beam Headlamp
52 Right High-Beam Headlamp
53 Left Low-Beam Headlamp
54 Right Low-Beam Headlamp
55 Wipers Fuses
Usage
56 Canister Vent Solenoid
58 Body Control Module 2
59 Body Control Module 1 61 Engine Oil Solenoid
62 O2 Sensor 2
63 –
64 Mass Airflow/ Canister Vent
65 Ignition Coils/Injectors –Odd
66 Daytime Running Lamps 2
67 Daytime Running Lamps 1
68 Auxiliary Stoplamps
69 External Power for Trailer
70 Upfitter Stoplamps 71 Fuel Heater/FlexFuel Sensor
72 Body Control Module 6