trailer CHEVROLET EXPRESS CARGO 2021 Owner's Guide

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
Driving and Operating 175
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, seeTow/Haul Mode 0145.
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 0164.
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 sway is increasing, the vehicle
brakes are selectively applied at each wheel,
to help reduce excessive trailer sway.
If TSC is enabled, the Traction Control
System (TCS)/StabiliTrak/ESC warning light
will flash on the instrument cluster. Reduce
vehicle speed by gradually removing your
foot from the accelerator. If trailer sway
continues, StabiliTrak/ESC can reduce engine
torque to help slow the vehicle. TSC will not
function if StabiliTrak/ESC is turned off. See
Traction Control/Electronic Stability Control
0 147.
{Warning
Trailer sway can result in a crash and in
serious injury or death, even if the
vehicle is equipped with TSC.
If the trailer begins to sway, reduce
vehicle speed by gradually removing your
foot from the accelerator. Then pull over
to check the trailer and vehicle to help
correct possible causes, including an
improperly or overloaded trailer,
(Continued)

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14583525) - 2021 - CRC - 12/9/20
176 Driving and Operating
Warning (Continued)
unrestrained cargo, improper trailer hitch
configuration, or improperly inflated or
incorrect vehicle or trailer tires. See
Towing Equipment0172 for trailer
ratings and hitch setup recommendations.
Trailer Tires
Special Trailer (ST) tires differ from vehicle
tires. Trailer tires are designed with stiff
sidewalls to help prevent sway and to
support heavy loads. These features can
make it difficult to determine if the trailer
tire pressures are low only based on a visual
inspection.
Always check all trailer tire pressures before
each trip when the tires are cool. Low trailer
tire pressure is a leading cause of trailer tire
blow-outs.
Trailer tires deteriorate over time. The trailer
tire sidewall will show the week and year
the tire was manufactured. Many trailer tire
manufacturers recommend replacing tires
more than six years old. Overloading is another leading cause of
trailer tire blow-outs. Never load your trailer
with more weight than the tires are
designed to support. The load rating is
located on the trailer tire sidewall.
Always know the maximum speed rating for
the trailer tires before driving. This may be
significantly lower than the vehicle tire
speed rating. The speed rating may be on
the trailer tire sidewall. If the speed rating is
not shown, the default trailer tire speed
rating is 105 km/h (65 mph).
Conversions and Add-Ons
Add-On Electrical Equipment
{Warning
The Data Link Connector (DLC) is used for
vehicle service and Emission Inspection/
Maintenance testing. See
Malfunction
Indicator Lamp (Check Engine Light) 076.
A device connected to the DLC —such as
an aftermarket fleet or driver-behavior
tracking device —may interfere with
vehicle systems. This could affect vehicle (Continued)
Warning (Continued)
operation and cause a crash. Such devices
may also access information stored in the
vehicle’s systems.
Caution
Some electrical equipment can damage
the vehicle or cause components to not
work and would not be covered by the
vehicle warranty. Always check with your
dealer before adding electrical equipment.
Add-on equipment can drain the vehicle's
12-volt battery, even if the vehicle is not
operating.
The vehicle has an airbag system. Before
attempting to add anything electrical to the
vehicle, see Servicing the Airbag-Equipped
Vehicle 044 and
Adding Equipment to the Airbag-Equipped
Vehicle 045.

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14583525) - 2021 - CRC - 12/9/20
Vehicle Care 187
How to Check Automatic Transmission
Fluid
Because this operation can be difficult, it is
recommended to have this check done at
your dealer, 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.
Caution
Too much or too little fluid can damage
the transmission. Too much can mean
that some of the fluid could come out
and fall on hot engine parts or exhaust
system parts, starting a fire. Too little
fluid could cause the transmission to
overheat. Be sure to get an accurate
reading if checking the transmission fluid.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 the outside
temperature 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 24 km
(15 mi) 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.
Checking the Fluid Level
Prepare the vehicle:
1. Park the vehicle on a level place. Keep the engine running.
2. With the parking brake applied, place the shift lever in P (Park).
3. With a foot on the brake pedal, move the shift lever through each gear range,
pausing for about three seconds in each
range. When M is reached, move the
selector from M1 through M3. Then,
position the shift lever in P (Park).

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14583525) - 2021 - CRC - 12/9/20
Vehicle Care 195
If Steam is Coming from the Engine
Compartment
{Warning
Steam and scalding liquids from a hot
cooling system are under pressure.
Turning the pressure cap, even a little,
can cause them to come out at high
speed and you could be burned. Never
turn the cap when the cooling system,
including the pressure cap, is hot. Wait
for the cooling system and pressure cap
to 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 Trailer Towing 0164. If the overheat warning is displayed with no
sign of steam:
1. Turn the air conditioning off.
2. Turn the heater on to the highest temperature and to the highest fan
speed. Open the windows as necessary.
3. When it is safe to do so, pull off the road, shift to P (Park) or N (Neutral) and
let the engine idle.
If the engine coolant temperature gauge is
no longer in the overheat zone or an
overheat warning no longer displays, the
vehicle can be driven. Continue to drive the
vehicle slowly for about 10 minutes. Keep a
safe vehicle distance from the vehicle in
front. If the warning does not come back on,
continue to drive normally and have the
cooling system checked for proper fill and
function.
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 parked. If the
warning is still on, turn off the engine until
it cools down. If the decision is made not to lift the hood,
get service help right away.
Engine Fan
The 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 an increase in fan noise may be heard.
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.
This fan noise may be heard when starting
the engine. It will go away as the fan clutch
partially disengages.

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

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14583525) - 2021 - CRC - 12/9/20
Vehicle Care 209
FusesUsage
68 Auxiliary stoplamps
69 External power for trailer
70 Upfitter stoplamps 71 Fuel heater/FlexFuel sensor
72 Body control module 6
73 Lighter/Data link connector
74 Front blower 75 Engine control module
76 Soot sensors (Diesel only)
77 O2 sensor 1
78 Engine control module/ Powertrain signal 1
79 Ignition coils/injectors - even Relays
Usage
15 Run/Crank
37 NOX Sensor (Diesel only)
38 Fuel pump
39 Crank
40 A/C compressor 48 Electro viscous fan clutch (Diesel only)
49 Powertrain 50 –
57 –
60 – Auxiliary Fuse Block
This component is near the fuse block in the
engine compartment
Fuses Usage
MR-1 Upfitter 1
MR-2 Upfitter 2
MR-3 Upfitter power control
Relays Usage
MR Rel 1 Upfitter 1
MR Rel 2 Upfitter 2

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14583525) - 2021 - CRC - 12/9/20
Vehicle Care 211
The vehicle may not be equipped with all of
the fuses, relays, and features shown.Mini-Fuses Usage
F1 –
F2 Steering wheel sensor
F3 Auxiliary parking lamps
F4 Front parking lamps F5 Trailer parking lamps
F6 Upfitter/Parking lamps F7 Right rear parking lamp
F8 Left rear parking lamp
F9 Exterior rear mirror switch/ Door
lock-unlock control
upfitter/Front camera
module
F10 Airbag/Automatic occupant sensing
F11 –/OnStar
F12 –
F13 HVAC 2
F14 HVAC 1 F15 Reflected LED display Mini-Fuses Usage
F16 Upfitter aux 1/Gas ambulance
F17 Heated outside mirrors
F18 Rear window defogger
F19 Compass
F20 Radio/Chime/SiriusXM satellite radio
F21 Remote function actuator/Tire pressure
monitor
F22 Ignition switch/Discrete logic ignition sensor
F23 Instrument cluster
F24 –
F25 HVAC control
F26 Auxiliary/Trailer reverse lamps
F27 Reverse tail lamps
F28 Upfitter 2/Reading lamps/Ambulance
F29 Rear blower
F30 Upfitter/Courtesy lamps Mini-Fuses Usage
F31 Front door lock
F32 Rear door lock
F33 Cargo door unlock
F34 Front passenger door unlock
F35 Rear passenger door unlock
F36 Driver door unlock F37 –
F38 –
Relays Usage K1 Run
K2 –
K3 Parking lamps
K4 Upfitter 2 K5 Rear window defogger
K6 Retained accessory power

Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14583525) - 2021 - CRC - 12/9/20
240 Vehicle Care
Towing the Vehicle
Caution
Incorrectly towing a disabled vehicle may
cause damage. The damage would not be
covered by the vehicle warranty. Do not
lash or hook to suspension components.
Use the proper straps around the tires to
secure the vehicle. Do not drag a locked
wheel/tire. Use tire skates or dollies
under any locked wheel/tire while
loading the vehicle. Do not use a sling
type lift to tow the vehicle. This could
damage the vehicle.
Caution
Improper use of the tow eye can damage
the vehicle. If equipped, use the tow eye
to load a disabled vehicle onto a flatbed
tow truck from a flat road surface, or to
move the vehicle a short distance. Use
caution and low speeds. The transmission
must be in (N) Neutral when moving the
vehicle.GM recommends a flatbed tow truck to
transport a disabled vehicle. Use ramps to
help reduce approach angles, if necessary.
A towed vehicle should have its drive wheels
off the ground. Contact Roadside Assistance
or a professional towing service if the
disabled vehicle must be towed.
Front Attachment Points
The vehicle is equipped with specific
attachment points to be used to pull the
vehicle onto a flatbed car carrier from a flat
road surface. Do not use these attachment
points to pull the vehicle from snow, mud
or sand.
Recreational Vehicle Towing
Recreational vehicle towing means towing
the vehicle behind another vehicle, such as
behind a motor home. The two most
common types of recreational vehicle
towing are known as dinghy towing and
dolly towing. Dinghy towing is towing the
vehicle with all four wheels on the ground.
Dolly towing is towing the vehicle with two
wheels on the ground and two wheels up
on a device known as a dolly.
Here are some important things to consider
before recreational vehicle towing:
.Before towing the vehicle, become
familiar with the local laws that apply to
recreational vehicle towing. These laws
may vary by region.
.What is the towing capacity of the
towing vehicle? Be sure to read the tow
vehicle manufacturer's recommendations.
.What is the distance that will be
traveled? Some vehicles have restrictions
on how far and how long they can tow.
.Is the proper towing equipment going to
be used? See your dealer or trailering
professional for additional advice and
equipment recommendations.