2020 GMC SIERRA DENALI trailer

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
294 Driving and Operating
The gross combined weight can
also be confirmed by weighing the
truck and trailer on a public scale.
The truck and trailer should be
loaded for the trip with passengers
and cargo.
Gross Vehicle Weight
Rating (GVWR)
For information about the vehicle's
maximum load capacity, seeVehicle
Load Limits 0200. When calculating
the GVWR with a trailer attached,
the trailer tongue weight must be
included as part of the weight the
vehicle is carrying.
Maximum Trailer Weight
The maximum trailer weight rating is
calculated assuming the tow vehicle
has a driver, a front seat passenger,
and all required trailering
equipment. This value represents
the heaviest trailer the vehicle can
tow, but it may be necessary to
reduce the trailer weight to stay
within the GCWR, GVWR, maximum
trailer tongue load, or GAWR-RR for
the vehicle.
Use the Tow Rating Guide
(my.gmc.com/learn) to determine
how much the trailer can weigh,
based on the vehicle model and
options.
Weights listed apply for
conventional trailers and
gooseneck/fifth-wheel trailers unless
otherwise noted.
A step bumper trailer hitch can only
support a total trailer weight up to
2 271 kg (5,000 lb). If a trailer hitch
ball is added to the step bumper,
check the hitch ball rating to be sure
it is higher than the total trailer
weight.
Maximum Trailer Tongue
Weight Rating
The Maximum Trailer Tongue
Weight Rating is the allowable
trailer tongue weight that the vehicle
can support using a conventional
trailer hitch. It may be necessary to
reduce the overall trailer weight to
stay within the maximum trailer
tongue weight rating while still
maintaining the correct trailer load
balance. A fifth-wheel or gooseneck
hitch may support a higher tongue
weight.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Driving and Operating 295
The Maximum Trailer Tongue
Weight Rating for a conventional
trailer hitch or a fifth wheel/
gooseneck hitch is shown on the
Trailering Information Label.
Do not exceed a maximum trailer
tongue weight of 567 kg (1,250 lb)
for a conventional trailer hitch.
The trailer tongue weight contributes
to the Gross Vehicle Weight (GVW).
GVW includes the curb weight of
your vehicle, any passengers,
cargo, equipment and the trailer
tongue weight. Vehicle options,
passengers, cargo, and equipment
reduce the maximum allowable
tongue weight the vehicle can carry,
which also reduces the maximum
allowable trailer weight.
Trailer Load Balance
The correct trailer load balance
must be maintained to ensure trailer
stability. Incorrect load balance is a
leading cause of trailer sway.
The trailer tongue weight (1) should
be 10–15% and fifth-wheel or
gooseneck tongue weight should be
15–25% of the total loaded trailer
weight (2). Some specific trailer
types, such as boat trailers, fall
outside of this range. Always refer
to the trailer owner’s manual for the
recommended trailer tongue weight
for each trailer. Never exceed the
maximum loads for the vehicle,
hitch, and trailer.
The trailer load balance percentage
is calculated as: weight (1) divided
by weight (2) times 100. After loading the trailer, separately
weigh the trailer and then the trailer
tongue and calculate the trailer load
balance percentage to see if the
weights and distribution are
appropriate for your vehicle. If the
trailer weight is too high, it may be
possible to transfer some of the
cargo into your vehicle. If the trailer
tongue weight is too high or too low,
it may be possible to rearrange
some of the cargo inside of the
trailer.
Do not exceed the maximum
allowable tongue weight for your
vehicle. Use the shortest hitch
extension available to position the
hitch ball closer to your vehicle. This
will help reduce the effect of the
trailer tongue weight on the trailer
hitch and the rear axle.
If a cargo carrier is used in the
trailer hitch receiver, choose a
carrier that positions the load as
close to the vehicle as possible.
Make sure the total weight,
including the carrier, is no more than

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
296 Driving and Operating
half of the maximum allowable
tongue weight for the vehicle or
227 kg (500 lb), whichever is less.
Rear Gross Axle Weight Rating
(GAWR-RR)
The GAWR-RR is the total weight
that can be supported by the rear
axle of the vehicle. Do not exceed
the GAWR-RR for the vehicle, with
the tow vehicle and trailer fully
loaded for the trip including the
weight of the trailer tongue. If using
a weight-distributing hitch, do not
exceed the GAWR-RR before
applying the weight distribution
spring bars.
The GAWR-RR for the vehicle is on
the Trailering Information Label.
Ask your dealer for trailering
information or assistance.
Towing Equipment
Hitches
Conventional Hitch
A conventional hitch is bolted to the
frame or cross member of the tow
vehicle, and is generally rated Class
2, 3, or 4.Gooseneck Hitch
A gooseneck hitch is designed to be
coupled to a special hitch leveraging
a hitch ball, and is mounted over the
rear axle in the truck bed.
Fifth-Wheel Hitch
A fifth-wheel hitch is mounted over
the rear axle in the truck bed, and
leverages a hinged plate
—the
same type of hitch leveraged by
semi trucks. Generally, fifth-wheel
hitches accommodate large trailers
with as many as one, two, or three
axles.
Always use the correct hitch
equipment for your vehicle.
Crosswinds, large trucks going by,
and rough roads can affect the
trailer and the hitch.
Proper hitch equipment for your
vehicle helps maintain control of the
vehicle-trailer combination. Many
trailers can be towed using a
weight-carrying hitch which has a
coupler latched to the hitch ball, or a
tow eye latched to a pintle hook.
Other trailers may require a
weight-distributing hitch that uses

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Driving and Operating 297
spring bars to distribute the trailer
tongue weight between your vehicle
and trailer axles. Fifth-wheel and
gooseneck hitches may also be
used. See“Maximum Trailer Tongue
Weight ”under Trailer Towing 0292
for weight limits with various hitch
types.
Avoid sharp turns when using a
step-bumper hitch to prevent
damage. Make wider turns to
prevent contact between your trailer
and your bumper.
Consider using mechanical sway
controls with any trailer. Ask a
trailering professional about sway
controls or refer to the trailer
manufacturer's recommendations
and instructions.
Weight-Distributing Hitch and
Adjustment
A weight-distributing hitch may be
useful with some trailers. Use the
following guidelines to determine if a
weight-distributing hitch should
be used.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
298 Driving and Operating
Vehicle SeriesTrailer WeightWeight-Distributing Hitch
Usage Hitch Distribution
1500 Up to 3 175 kg (7,000 lb) Not Required 50%
1500 Over 3 175 kg (7,000 lb) Required50%
2500/3500 Up to 9 080 kg (20,000 lb) Not Required 25%
1. Front of Vehicle
2. H1/H2 Body to Ground
Distance
Towing with Model 1500 Trucks
1. Position the truck so that the trailer is ready to connect.
Keep the trailer detached.
2. Measure the height of the top of the front wheel opening at
the fender to the ground (H1).
3. Attach the vehicle to the trailer. Do not attach weight
distribution bars at this time.
4. Measure the height of the top of the front wheel opening on
the fender to the ground (H2). 5. Install and adjust the tension in
the weight-distributing bars per
the manufacturers’
recommendations so that the
height of the front fender is
approximately H2−[(H2−H1)/2]
(halfway between the two
measured ride heights).
6. Visually inspect the trailer and weight-distributing hitch to
ensure that the manufacturers’
recommendations have
been met.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Driving and Operating 299
MeasurementHeight Example 1500 (mm)
H1 1 000
H2 1 050
H2−H1 50
(H2−H1)/2 25
H2−[(H2−H1)/2] 1 025
Towing with Model 2500/3500
Trucks 1. Position the truck so that the trailer is ready to connect.
Keep the trailer detached.
2. Measure the height of the top of the front wheel opening at
the fender to the ground (H1).
3. Attach the vehicle to the trailer. Do not attach weight
distribution bars at this time.
4. Measure the height of the top of the front wheel opening on
the fender to the ground (H2). 5. Install and adjust the tension in
the weight-distributing bars per
the manufacturers’
recommendations so that the
height of the front fender is
approximately H2−[(H2−H1)/4]
(1/4 the difference between the
two measured ride heights,
below the secondary ride
height {H2}).
6. Visually inspect the trailer and weight-distributing hitch to
ensure that the manufacturers’
recommendations have
been met.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
300 Driving and Operating
MeasurementHeight Example 2500/3500 (mm)
H1 1 040
H2 1 080
H2−H1 40
(H2−H1)/4 10
H2−[(H2−H1)/4] 1 070
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 Tires0379 for
instructions on proper tire
inflation.
Fifth-Wheel and Gooseneck
Trailering
Fifth-wheel and gooseneck trailers
can be used with many pickup
models. These trailers place a
larger percentage of the weight
(kingpin weight) on the tow vehicle
than conventional trailers. Make sure this weight does not cause the
vehicle to exceed GAWR or GVWR.
Fifth-wheel or gooseneck kingpin
weight should be 15–25% of the
trailer weight up to the maximum
amount specified in the trailering
chart for the vehicle. See
“Trailer
Weight" under Trailer Towing0292.
The hitch should be in the pickup
bed so that its centerline is over or
slightly in front of the rear axle. Take
care that it is not so far forward that
it will contact the back of the cab in
sharp turns. This is especially
important for short box pickups.
Trailer pin box extensions and
sliding fifth-wheel hitch assemblies
may be used. There should be at
least 15 cm (6 in) of clearance between the top of the pickup box
and the bottom of the trailer shelf
that extends over the box.
Make sure the hitch is attached to
the tow vehicle frame rails. Do not
use the pickup box for support.
Safety Chains
Always attach safety chains
between the vehicle and the trailer.
Instructions about safety chains
may be provided by the hitch
manufacturer or by the trailer
manufacturer.
If the trailer being towed weighs up
to 2 271 kg (5,000 lb) with a
factory-installed step bumper, safety
chains may be attached to the

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Driving and Operating 301
attaching points on the bumper;
otherwise, safety chains should be
attached to holes on the trailer hitch.
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 enough slack in
the safety chains to allow the
combination to turn. Never allow
safety chains to drag on the ground.
Trailer Brakes
Loaded trailers over 900 kg
(2,000 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, andmaintained properly. Never attempt
to tap into your vehicle's hydraulic
brake system. If you do, both the
vehicle antilock brakes and the
trailer brakes may not function,
which could result in a crash.
Auxiliary Battery
If equipped, the vehicle's auxiliary
battery can be used to supply
electrical power to additional
equipment that may be added, such
as a slide-in camper.
Locate the auxiliary battery
connector under the hood on the
driver side of the vehicle, next to the
engine compartment fuse block.
Follow the proper installation
instructions included with any
electrical equipment that is installed.
Caution
To prevent draining the auxiliary
battery, always turn off electrical
equipment when not in use and
do not use any equipment that
(Continued)
Caution (Continued)
may exceed the
maximum amperage rating of
30 amps.
Trailer Wiring Harness
Basic Trailer Wiring
If the vehicle is not equipped with a
trailer connector on the rear bumper,
a 7-wire trailering harness is tied to
the vehicles 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 contains
the following trailer circuits:
Stop/Turn
Signal Left Yellow/Blue
Stop/Turn
Signal Right Green/Violet