2021 CHEVROLET EXPRESS CARGO wiring

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14583525) - 2021 - CRC - 12/9/20
Seats and Restraints 45
Warning (Continued)
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 speakersYour 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 0225 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 0267.
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 074.
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
(Continued)
Caution (Continued)
broken airbag coverings, have the airbag
covering and/or airbag module replaced.
For the location of the airbags, see Where
Are the Airbags? 038. See your dealer
for service.
Replacing Airbag System Parts
after a Crash
{Warning
A crash can damage the airbag systems
in the vehicle. A damaged airbag system
may not properly protect you and your
passenger(s) in a crash, resulting in
serious injury or even death. To help
make sure the airbag systems are
working properly after a crash, have
them inspected and any necessary
replacements made as soon as possible.
If an airbag inflates, you will need to
replace airbag system parts. See your dealer
for service.

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14583525) - 2021 - CRC - 12/9/20
74 Instruments and Controls
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. The system
check includes the airbag sensor(s), the
pretensioners (if equipped), the airbag
modules, the wiring, and the crash sensingand diagnostic module. For more
information on the airbag system, see
Airbag System
036.
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 display.

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14583525) - 2021 - CRC - 12/9/20
Driving and Operating 163
Parking on Hills
{Warning
To prevent serious injury or death,
always park your vehicle and trailer on a
level surface when possible.
When parking your vehicle and your trailer
on a hill: 1. Press the brake pedal, but do not shift into P (Park) yet. Turn the wheels into
the curb if facing downhill or into traffic
if facing uphill.
2. Have someone place chocks under the trailer wheels.
3. When the wheel chocks are in place, gradually release the brake pedal to
allow the chocks to absorb the load of
the trailer.
4. Reapply the brake pedal. Then apply the parking brake and shift into P (Park).
5. Release the brake pedal.
Leaving After Parking on a Hill
1. Apply and hold the brake pedal.
.Start the engine.
.Shift into a gear.
.Release the parking brake. 2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of
the 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.

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14583525) - 2021 - CRC - 12/9/20
Driving and Operating 173
1. Front of Vehicle
2. Body to Ground Distance
When using a weight-distributing hitch,
measure the front fender height distance (2)
before connecting the trailer. Adjust the
spring bars until the front fender height
distance (2) is the same height before the
trailer was connected. Do not reduce the
front fender height below the initial
distance (2).
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
0 212 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
trailers to have their own braking system if
the loaded weight of the trailer exceeds
certain minimums that can 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.

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14583525) - 2021 - CRC - 12/9/20
174 Driving and Operating
The seven-wire harness contains the
following trailer circuits:Stop/Turn
Signal Left* Yellow
Stop/Turn Signal
Right* Dark Green
Tail/Parking
Lamps** Brown
Reverse Lamps** Light Green
Battery Feed Red/Black
Ground White
Electric Trailer Brake Dark Blue
*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. Heavy-Duty Trailer Wiring Harness Package
lf equipped, the trailer wiring harness, with
a seven-pin connector is mounted on the
trailer hitch.
1. Left Turn/Brake
2. Taillamps
3. Reverse Lamps
4. Battery Feed
5. Right Turn/Brake
6. Electric Brakes
7. Ground
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:
Electric Trailer
Brakes Dark Blue
Battery Feed Red/White
Brake Apply Signal Light Blue
Ground Black
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.

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14583525) - 2021 - CRC - 12/9/20
Vehicle Care 205
To replace one of these bulbs:1. Remove the screws (3) that secure the license plate bulb assembly (2).
2. Turn the bulb socket (1) counterclockwise and pull the bulb straight out of the
socket.
3. Install the new bulb.
4. Reverse Steps 1 and 2 to reinstall the license plate bulb assembly.
Electrical System
Electrical System Overload
The vehicle has fuses and circuit breakers 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 and circuit breakers protect power
devices in the vehicle.
Replace a bad fuse with a new one of the
identical size and rating.
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.
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.
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.

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14583525) - 2021 - CRC - 12/9/20
Vehicle Care 207
The vehicle may not be equipped with all of
the fuses, relays, and features shown.Fuses Usage
1 ABS motor
2 ABS module
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

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14583525) - 2021 - CRC - 12/9/20
208 Vehicle Care
FusesUsage
18 A/C
19 Engine control module battery
20 Left stop/turn cutaway lamp
21 Left stop/turn trailer lamp
22 Right stop/turn cutaway lamp
23 NOX Sensor (Diesel only)
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 Fuses
Usage
32 Transmission control module 1 battery
33 Rear parking aid module
34 NOX Sensor (Diesel only)
35 Fuel heater control module (Diesel only)
36 Fuel system control module battery
41 Transmission control module 2, battery
signal
42 Trailer wiring
43 Electro viscous fan clutch (Diesel only)
44 Starter solenoid 45 Engine control module, powertrain signal 2
46 DC-AC inverter 47 –
51 Left high-beam headlamp Fuses
Usage
52 Right high-beam headlamp
53 Left low-beam headlamp
54 Right low-beam headlamp
55 Wipers
56 Canister vent solenoid
58 Body control module 2
59 Body control module 1 61 Engine oil solenoid/ Crankcase vent heater
(Diesel only)
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