wiring CHEVROLET EXPRESS 2020 Get To Know Guide

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
13882570) - 2020 - CRC - 11/1/19
54 Seats and Restraints
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, see
Publication Ordering Information
0330.
{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 0272 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 0323.
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 090.

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
13882570) - 2020 - CRC - 11/1/19
90 Instruments and Controls
Voltmeter Gauge
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
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 sensing and diagnostic

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
13882570) - 2020 - CRC - 11/1/19
200 Driving and Operating
Warning (Continued)
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.
. 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.
Maintenance when Trailer
Towing
The vehicle needs service more
often when used to tow trailers. See
Maintenance Schedule 0305. It is

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
13882570) - 2020 - CRC - 11/1/19
Driving and Operating 209
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. See Tires0255 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.

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
13882570) - 2020 - CRC - 11/1/19
210 Driving and Operating
Use only a round, seven-wire
connector with flat blade terminals
meeting SAE J2863 specifications
for proper electrical connectivity.
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

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
13882570) - 2020 - CRC - 11/1/19
Driving and Operating 211
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.
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 0175.
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 ”under Trailer
Towing 0201.
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
Operating the vehicle in Tow/Haul
Mode when lightly loaded or not
towing will not cause damage;
however, it is not recommended and
may result in unpleasant engine and
transmission driving characteristics
and reduced fuel economy.
Trailer Sway
Control (TSC)
Vehicles with StabiliTrak/Electronic
Stability Control (ESC) have a
Trailer Sway Control (TSC) feature.
Trailer sway is unintended
side-to-side motion of a trailer while
towing. If the vehicle is towing a
trailer and the TSC detects that

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
13882570) - 2020 - CRC - 11/1/19
248 Vehicle Care
2. License Plate BulbAssembly
3. Screws
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.

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
13882570) - 2020 - CRC - 11/1/19
Vehicle Care 249
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 fires caused by electrical
problems.
Look at the silver-colored band
inside the fuse. If the band is broken
or melted, replace the fuse. Be sure
you replace a bad fuse with a new
one of the identical size and rating.
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-
13882570) - 2020 - CRC - 11/1/19
250 Vehicle Care
The vehicle may not be equipped
with all of the fuses, relays, and
features shown.Fuses
Usage
1 ABS motor
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

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
13882570) - 2020 - CRC - 11/1/19
Vehicle Care 251
FusesUsage
19 Engine control module battery
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 Fuses
Usage
31 Transmission control module
Ignition
32 Transmission control module 1
battery
33 Rear parking aid module
34 –
35 –
36 Fuel system control module battery
41 Transmission control module 2,
battery signal
42 Trailer wiring
43 –
44 Starter solenoid
45 Engine control module, powertrain
signal 2
46 DC-AC inverter
47 – Fuses
Usage
51 Left high-beam headlamp
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
62 O2 sensor 2
63 –
64 Mass airflow/ Canister vent
65 Ignition coils/ injectors - odd