trailer GMC TERRAIN 2021 Owner's Guide

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
Driving and Operating 255
.Tires must be properly inflated to support
loads while towing a trailer. SeeTires
0 287 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 450 kg (1,000 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 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.
Trailer Tires
Special Trailer (ST) tires differ from vehicle
tires. Trailer tires are designed with stiff
sidewalls to help prevent sway and tosupport 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).

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
270 Vehicle Care
By this time, the coolant level inside the
coolant surge tank may be lower. If the
level is lower, add more of the proper
mixture to the coolant surge tank until
the level reaches the indicated
level mark.
5. Replace the pressure cap tightly.
6. Verify coolant level after the engine is shut off and the coolant is cold.
If necessary, repeat coolant fill procedure
Steps 1–6.
If the coolant still is not at the proper
level when the system cools down again,
see your dealer.
Caution
If the pressure cap is not tightly installed,
coolant loss and engine damage may
occur. Be sure the cap is properly and
tightly secured.
Engine Overheating
The vehicle has an engine coolant
temperature gauge on the instrument
cluster and overheat messages in the Driver
Information Center (DIC) to warn of engine
overheating. See Engine Coolant
Temperature Gauge 091. The decision may be made not to lift the
hood when the engine coolant temperature
gauge is in the overheat zone or an engine
overheat DIC message displays, but instead
to get service help right away. See
Roadside
Assistance Program 0349.
If the decision to lift the hood is made,
make sure the vehicle is parked on a level
surface. Then check to see if the engine
cooling fan(s) are running. If the engine is
overheating, the fan(s) should be running.
If they are not, do not continue to run the
engine, and have the vehicle serviced.
Caution
Do not run the engine if there is a leak
in the engine cooling system. This can
cause a loss of all coolant and can
damage the system and vehicle. Have
any leaks fixed right away.
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 the engine coolant temperature gauge is
in the overheat zone or an engine overheat
DIC message 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

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
282 Vehicle Care
The vehicle may not be equipped with all of
the fuses, relays, and features shown.Fuses Usage
F01 Starter 1
F02 Starter 2
F03 Lambda sensor 1
F04 Engine control module F05 FlexFuel sensor/Aero shutter Fuses Usage
F06 Transmission control module
F07 –
F08 Engine control module
F09 Air conditioning clutch F10 Canister vent solenoid F11 Fuel system
F12 Front heated seats Fuses Usage
F13 Engine coolant pump
F14 –
F15 Lambda sensor 2
F16 Ignition coils F17 Engine control module
F18 –
F19 –
F20 DC DC converter 2 F21 Shift control
F22 Antilock brake pump
F23 Front/Rear washer pump
F24 –
F25 –
F26 –
F27 Antilock brake valves
F28 LD trailer
F29 Rear window defogger
F30 Mirror defroster F31 –
F32 Variable functions

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
284 Vehicle Care
Instrument Panel Fuse Block
The instrument panel fuse block is under the
instrument panel on the driver side.
To access the fuses, press and release the
latch near the top center square.
Apply pressure to the two retaining tabs on
the sides of the cover, until the two
retaining tabs clear the sides of the
instrument panel. Allow the panel to move
downward and out of the way.
To reinstall the cover, reverse the steps.
The vehicle may not be equipped with all of
the fuses and relays shown.
FusesUsage
F01 DC AC inverter
F02 Front windows Fuses
Usage
F03 Trailer brake
F04 Heating, ventilation, and air conditioning blower
F05 –
F06 Central gateway module F07 –
F08 Body control module 3
F09 Amplifier F10 –
F11 –
F12 –
F13 –
F14 Electronic shifter F15 Transmission control module
F16 Front heated seats F17 Left data link connector
F18 Body control module 7
F19 Exterior mirror
F20 –

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
286 Vehicle Care
Remove the trim plate to access the fuse
block.
The vehicle may not be equipped with all of
the fuses and relays shown.
FusesUsage
F1 –
F2 Liftgate Fuses
Usage
F3 Trailer auxiliary power
F4 Power seat co-driver F5 Memory seat module
F6 Sunroof F7 Side blind zone alert
F8 Trailer reverse lamps
F9 Rear heated seat 1
F10 Park lamps F11 Rear heated seat 2
F12 –
F13 Trailer parking lamp
F14 Right trailer stoplamp/ Turn signal lamp
F15 Left parking lamp
F16 Right parking lamp F17 Video processing module
F18 Left trailer stoplamp/ Turn signal lamp
F19 All-wheel drive
F20 Lumbar

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
Vehicle Care 287
FusesUsage
F21 Rear auxiliary power outlet
F22 Rear drive unit
Relays Usage
K1 Right trailer stoplamp/ Turn signal lamp
K2 Trailer reverse lamps
K3 Left trailer stoplamp/ Turn signal lamp
K4 Park lamps K5 –
Wheels and Tires
Tires
Every new GM vehicle has high-quality
tires made by a leading tire
manufacturer. See the warranty manual
for information regarding the tire
warranty and where to get service. For
additional information refer to the tire
manufacturer.
{Warning
.Poorly maintained and improperly
used tires are dangerous.
.Overloading the tires can cause
overheating as a result of too
much flexing. There could be a
blowout and a serious crash. See
Vehicle Load Limits 0196.
.Underinflated tires pose the same
danger as overloaded tires. The
resulting crash could cause serious
injury. Check all tires frequently to
maintain the recommended
pressure. Tire pressure should be
checked when the tires are cold.
.Overinflated tires are more likely
to be cut, punctured, or broken by
a sudden impact —such as when
hitting a pothole. Keep tires at the
recommended pressure.
.Worn or old tires can cause a
crash. If the tread is badly worn,
replace them.
(Continued)
Warning (Continued)
.Replace any tires that have been
damaged by impacts with
potholes, curbs, etc.
.Improperly repaired tires can cause
a crash. Only the dealer or an
authorized tire service center
should repair, replace, dismount,
and mount the tires.
.Do not spin the tires in excess of
56 km/h (35 mph) on slippery
surfaces such as snow, mud, ice,
etc. Excessive spinning may cause
the tires to explode.
All-Season Tires
This vehicle may come with all-season tires.
These tires are designed to provide good
overall performance on most road surfaces
and weather conditions. Original equipment
tires designed to GM's specific tire
performance criteria have a TPC specification
code molded onto the sidewall. Original
equipment all-season tires can be identified
by the last two characters of this TPC code,
which will be “MS.”

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
320 Vehicle Care
Install the tow eye into the socket and turn
it until it is fully tightened.
When the tow eye is removed, reinstall the
cover with the notch in the original position.
To tow the vehicle behind another vehicle
for recreational purposes, such as behind a
motor home, seeRecreational Vehicle
Towing 0320.
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.
.The towing capacity of the towing
vehicle. Be sure to read the tow vehicle
manufacturer's recommendations.
.How far the vehicle will be towed. Some
vehicles have restrictions on how far and
how long they can tow.
.The proper towing equipment. See your
dealer or trailering professional for
additional advice and equipment
recommendations.
.If the vehicle is ready to be towed. Just
as preparing the vehicle for a long trip,
make sure the vehicle is prepared to be
towed.
Dinghy Towing
Caution
If the vehicle is towed with all four
wheels on the ground, the drivetrain
components could be damaged. The
repairs would not be covered by the
vehicle warranty. Do not tow the vehicle
with all four wheels on the ground.
The vehicle was not designed to be towed
with all four wheels on the ground. The
vehicle may be towed using a platform
trailer with all four wheels off the ground.
Some vehicles may be dolly towed. See the
following information on dolly towing.
Dolly Towing (All-Wheel-Drive Vehicles)
All-wheel-drive vehicles cannot be towed
with two wheels on the ground. To properly
tow these vehicles, they should be placed on
a platform trailer with all four wheels off of
the ground.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
Service and Maintenance 331
Because of the way people use vehicles,
maintenance needs vary. There may need to
be more frequent checks and services. The
Additional Required Services - Normal are for
vehicles that:
.Carry passengers and cargo within
recommended limits on the Tire and
Loading Information label. SeeVehicle
Load Limits 0196.
.Are driven on reasonable road surfaces
within legal driving limits.
.Use the recommended fuel. See
Recommended Fuel (LYX - 1.5L L4 Turbo
Engine) 0246.
Refer to the information in the Maintenance
Schedule Additional Required Services -
Normal chart.
The Additional Required Services - Severe are
for vehicles that are:
.Mainly driven in heavy city traffic in hot
weather.
.Mainly driven in hilly or mountainous
terrain.
.Frequently towing a trailer.
.Used for high speed or competitive
driving.
.Used for taxi, police, or delivery service. Refer to the information in the Maintenance
Schedule Additional Required Services -
Severe chart.
{Warning
Performing maintenance work can be
dangerous and can cause serious injury.
Perform maintenance work only if the
required information, proper tools, and
equipment are available. If they are not,
see your dealer to have a trained
technician do the work. See
Doing Your
Own Service Work 0259.
Maintenance Schedule
Owner Checks and Services
Check the engine oil level. See Engine Oil
0 262.
Once a Month
.Check the tire inflation pressures. See Tire
Pressure 0293.
.Inspect the tires for wear. See Tire
Inspection 0298.
.Check the windshield washer fluid level.
See Washer Fluid 0271.
Engine Oil Change
When the CHANGE ENGINE OIL SOON
message displays, have the engine oil and
filter changed within the next 1 000 km/
600 mi. If driven under the best conditions,
the engine oil life system may not indicate
the need for vehicle service for up to a year.
The engine oil and filter must be changed at
least once a year and the oil life system
must be reset. Your trained dealer technician
can perform this work. If the engine oil life
system is reset accidentally, service the
vehicle within 5 000 km/3,000 mi since the
last service. Reset the oil life system when
the oil is changed. See Engine Oil Life
System 0264.
Air Conditioning Desiccant (Replace Every
Seven Years)
The air conditioning system requires
maintenance every seven years. This service
requires replacement of the desiccant to
help the longevity and efficient operation of
the air conditioning system. This service can
be complex. See your dealer.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/-
Mexico-14420055) - 2021 - CRC - 11/13/20
374 Index
Storage Areas (cont'd)Center Console . . . . . . . . . . . . . . . . . . . . . . . . . 75
Convenience Net . . . . . . . . . . . . . . . . . . . . . . . . 76
Glove Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Roof Rack System . . . . . . . . . . . . . . . . . . . . . . . 76
Sunglasses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Storage Compartments . . . . . . . . . . . . . . . . . . . 74
Storing the Tire Sealant and
Compressor Kit . . . . . . . . . . . . . . . . . . . . . . . . . 310
Struts Gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276
Stuck Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
Summer Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288
Sun Visors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Sunglass Storage . . . . . . . . . . . . . . . . . . . . . . . . . 74
Sunroof . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Navigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
System Engine Air Filter Life . . . . . . . . . . . . . . . . . . . 265
Forward Collision Alert (FCA) . . . . . . . . . . . 237
Global Positioning . . . . . . . . . . . . . . . . . . . . . 148
Infotainment . . . . . . . . . . . . . . . . . . . . . . . . . . . 356
OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
Roof Rack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Systems
Driver Assistance . . . . . . . . . . . . . . . . . . . . . . 231T
Tachometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
Taillamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278
Teen Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
Text Telephone (TTY) Users . . . . . . . . . . . . . . 348
Theft-Deterrent Systems . . . . . . . . . . . . . . . . . . .23Immobilizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .81
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287 All-Season . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287
Buying New Tires . . . . . . . . . . . . . . . . . . . . . . 300
Chains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
Changing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310
Compact Spare . . . . . . . . . . . . . . . . . . . . . . . . 315
Designations . . . . . . . . . . . . . . . . . . . . . . . . . . . 290
Different Size . . . . . . . . . . . . . . . . . . . . . . . . . . 301
If a Tire Goes Flat . . . . . . . . . . . . . . . . . . . . . 303
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
Pressure Light . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Pressure Monitor Operation . . . . . . . . . . . 295
Pressure Monitor System . . . . . . . . . . . . . . 294
Rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
Sealant and Compressor Kit . . . . . . . . . . . . 305
Sealant and Compressor Kit,
Storing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310
Sidewall Labeling . . . . . . . . . . . . . . . . . . . . . . 288
Terminology and Definitions . . . . . . . . . . . 291 Tires (cont'd)
Uniform Tire Quality Grading . . . . . . . . . . 301
Wheel Alignment and Tire Balance . . . . 302
Wheel Replacement . . . . . . . . . . . . . . . . . . . . 302
When It Is Time for New Tires . . . . . . . . . 299
Winter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288
Top Tier Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246
Tow/Haul Mode . . . . . . . . . . . . . . . . . . . . . . . . . . 211
Tow/Haul Mode Light . . . . . . . . . . . . . . . . . . . . 96
Towing
Driving Characteristics . . . . . . . . . . . . . . . . . 249
Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254
General Information . . . . . . . . . . . . . . . . . . . 248
Recreational Vehicle . . . . . . . . . . . . . . . . . . . 320
Trailer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318
Traction Control System (TCS)/StabiliTrakLight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Off Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
Traction Control/Electronic Stability
Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .214
Trademarks and License Agreements . . . . . 169
Trailer Towing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
Transmission
Automatic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
Fluid, Automatic . . . . . . . . . . . . . . . . . . . . . . . 265