2013 GMC SIERRA See i

Black plate (87,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
Driving and Operating 9-87
VehicleAxle Ratio Maximum Trailer Weight GCWR (a)
6.0L V8 (Dual Rear Wheels) 3.733 946 kg (8,700 lbs) 7 257 kg (16,000 lbs)
6.0L V8 (Dual Rear Wheels) 4.105 987 kg (13,200 lbs) 9 299 kg (20,500 lbs)
(a) The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle
and trailer including any passengers, cargo, equipment, and conversions. The GCWR for the vehicle should not be
exceeded.
(b) This model is neither designed nor intended to tow fifth-wheel or gooseneck trailers.
Ask your dealer for trailering
information or advice.
Weight of the Trailer Tongue
The tongue load (A) of any trailer is
very important because it is also
part of the vehicle weight. The
Gross Vehicle Weight (GVW)
includes the curb weight of the
vehicle, any cargo carried in it, and
the people who will be riding in the
vehicle as well as trailer tongue
weight. Vehicle options, equipment,
passengers and cargo in the vehicle
reduce the amount of tongue weight
the vehicle can carry, which will also
reduce the trailer weight the vehicle can tow. See
“Vehicle Load Limits”
for more information about the
vehicle's maximum load capacity.
Trailer tongue weight (A) should be
10 to 15 percent and fifth-wheel or
gooseneck kingpin weight should be
15 to 25 percent of the loaded trailer
weight up to the maximums for
vehicle series and hitch type.

Black plate (88,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
9-88 Driving and Operating
Vehicle Series Hitch TypeMaximum Tongue
Weight
1500 Weight Carrying 363 kg (800 lb)
1500 Weight Distributing 499 kg (1,100 lb)
2500/3500
Standard Box Weight Carrying or
Weight Distributing 680 kg (1,500 lb)
2500/
3500 Long Box Weight Carrying or
Weight Distributing 907 kg (2,000 lb)
2500 Fifth-Wheel Gooseneck 1 361 kg (3,000 lb)
3500 Single Rear
Wheels Fifth-Wheel Gooseneck 1 814 kg (4,000 lb)
3500 Dual Rear
Wheels Fifth-Wheel Gooseneck 2 495 kg (5,500 lb)
Do not exceed the maximum
allowable tongue weight for the
vehicle. Choose the shortest hitch
extension that will position the hitch
ball closest to the vehicle. This will
help reduce the effect of trailer
tongue weight on the rear axle. Trailer rating may be limited by the
vehicle's ability to carry tongue
weight. Tongue or kingpin weight
cannot cause the vehicle to exceed
the GVWR (Gross Vehicle Weight
Rating) or the RGAWR (Rear Gross
Axle Weight Rating). See
“Total
Weight on the Vehicle's Tires” later
in this section for more information. After loading the trailer, weigh the
trailer and then the tongue,
separately, to see if the weights are
proper. If they are not, adjustments
might be made by moving some
items around in the trailer.
Total Weight on the Vehicle's
Tires
Be sure the vehicle's tires are
inflated to the inflation pressures
found on the Certification Tire label
on the drivers door or see
Vehicle
Load Limits on page 9‑15 for more
information. Make sure not to
exceed the GVWR limit for the
vehicle, or the RGAWR, with the tow
vehicle and trailer fully loaded for
the trip including the weight of the
trailer tongue. If using a
weight-distributing hitch, make sure
not to exceed the RGAWR before
applying the weight distribution
spring bars.

Black plate (89,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
Driving and Operating 9-89
Weight of the Trailering
Combination
It is important that the combination
of the tow vehicle and trailer does
not exceed any of its weight ratings
—GCWR, GVWR, RGAWR, Trailer
Weight Rating, or Tongue Weight.
The only way to be sure it is not
exceeding any of these ratings is to
weigh the tow vehicle and trailer
combination, fully loaded for the trip,
getting individual weights for each of
these items.
Towing Equipment
Hitches
The correct hitch equipment helps
maintain combination control. Many
trailers can be towed with a
weight-carrying hitch which simply
features 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 spring bars to distribute
the trailer tongue weight among the
two vehicle and trailer axles.
Fifth-wheel and gooseneck hitches
may also be used. See “Weight of
the Trailer Tongue” underTrailer
Towing on page 9‑73 for rating limits
with various hitch types. If a step-bumper hitch will be used,
the bumper could be damaged in
sharp turns. Make sure there
is ample room when turning to avoid
contact between the trailer and the
bumper.
Consider using 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.

Black plate (91,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
Driving and Operating 9-91
Fifth-wheel or gooseneck kingpin
weight should be 15 to 25 percent of
the trailer weight up to the maximum
amount specified in the trailering
chart for the vehicle. See“Weight of
the Trailer” underTrailer Towing on
page 9‑73 for more information.
The hitch should be located 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 can help this condition.
There should be at least six inches
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 chains between the
vehicle and the trailer. 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.
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 lbs) with a factory-installed
step bumper, safety chains may be
attached to the attaching points on
the bumper; otherwise, safety
chains should be attached to holes
on the trailer hitch platform. Always
leave just enough slack so the
combination can turn. Never allow
safety chains to drag on the ground.
Trailer Brakes
A loaded trailer that weighs more
than 900 kg (2,000 lbs) needs to
have its own brake system that is
adequate for the weight of the
trailer. Be sure to read and follow the instructions for the trailer brakes
so they are installed, adjusted, and
maintained properly.
Do not tap into the vehicle's
hydraulic brake system.
Auxiliary Battery
The auxiliary battery provision can
be used to supply electrical power
to additional equipment that may be
added, such as a slide-in camper.
If the vehicle has this provision, this
relay will be located on the driver
side of the vehicle, next to the
underhood electrical center.
Be sure to follow the proper
installation instructions included with
any electrical equipment that is
installed.
Notice:
Leaving electrical
equipment on for extended
periods will drain the battery.
Always turn off electrical
equipment when not in use and
do not use equipment that

Black plate (94,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
9-94 Driving and Operating
ITBC must be disconnected. Do not
power both ITBC and aftermarket
controllers to control the trailer
brakes at the same time.
Tow/Haul Mode
Pressing this button at the end of
the shift lever turns on and off the
Tow/Haul Mode.
This indicator light on the instrument
panel cluster comes on when the
Tow/Haul Mode is on.
Tow/Haul is a feature that assists
when pulling a heavy trailer or a
large or heavy load. SeeTow/Haul
Mode on page 9‑37 for more
information.
Tow/Haul is designed to be most
effective when the vehicle and
trailer combined weight is at least
75 percent of the vehicle's Gross
Combined Weight Rating (GCWR).
See “Weight of the Trailer” under
Trailer Towing on page 9‑73. Tow/
Haul is most useful under the
following driving conditions:
.When pulling a heavy trailer or a
large or heavy load through
rolling terrain.
.When pulling a heavy trailer or a
large or heavy load in
stop-and-go traffic.
.When pulling a heavy trailer or a
large or heavy load in busy
parking lots where improved low
speed control of the vehicle is
desired.
Operating the vehicle in Tow/Haul
when lightly loaded or with no trailer
at all will not cause damage.
However, there is no benefit to the
selection of Tow/Haul when the
vehicle is unloaded. Such a
selection when unloaded may result
in unpleasant engine and
transmission driving characteristics
and reduced fuel economy. Tow/
Haul is recommended only when
pulling a heavy trailer or a large or
heavy load.

Black plate (95,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
Driving and Operating 9-95
Integrated Trailer Brake
Control System
The vehicle may have an Integrated
Trailer Brake Control (ITBC) system
for electric trailer brakes.
This symbol is located on the Trailer
Brake Control Panel on vehicles
with an Integrated Trailer Brake
Control system. The power output to
the trailer brakes is based on the
amount of brake pressure being
applied by the vehicle’s brake
system. This available power output
to the trailer brakes can be adjusted
to a wide range of trailering
situations.
The ITBC system is integrated with
the vehicle’s brake, antilock brake,
and StabiliTrak (if equipped)
systems. In trailering conditions that cause the vehicle’s antilock brake or
StabiliTrak systems to activate,
power sent to the trailer's brakes will
be automatically adjusted to
minimize trailer wheel lock-up. This
does not imply that the trailer has
StabiliTrak.
The vehicle may have a Trailer
Sway Control (TSC) feature. See
Trailer Sway Control (TSC) on
page 9‑100.
The vehicle may have a Hill Start
Assist (HSA) feature. See
Hill Start
Assist (HSA) on page 9‑52.
If the vehicle’s brake, antilock brake,
or StabiliTrak systems are not
functioning properly, the ITBC
system may not be fully functional
or may not function at all. Make sure
all of these systems are fully
operational to ensure full
functionality of the ITBC system.
The ITBC system is powered
through the vehicle's electrical
system. Turning the ignition off will
also turn off the ITBC system. The ITBC system is fully functional only
when the ignition is in ON or
in RUN.
The ITBC system can only be used
with trailers with electric brakes.
{WARNING
Connecting a trailer that has a
surge, air,
or electric-over-hydraulic trailer
brake system may result in
reduced or complete loss of trailer
braking. There may be an
increase in stopping distance or
trailer instability which could
result in personal injury or
damage to the vehicle, trailer,
or other property. Use the ITBC
system only with electric brakes.

Black plate (96,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
9-96 Driving and Operating
Trailer Brake Control Panel
A. Manual Trailer Brake ApplyLever
B. Trailer Gain Adjustment Buttons
The ITBC system has a control
panel located on the instrument
panel to the left of the steering
column. See Instrument Panel
(Base/Uplevel Version) on page 1‑2
or Instrument Panel (Premium
Version) on page 1‑5 for more
information. The control panel
allows adjustment to the amount of
output, referred to as trailer gain, available to the electric trailer
brakes and allows manual
application of the trailer brakes. The
Trailer Brake Control Panel is used
along with the Trailer Brake Display
Page on the DIC to adjust and
display power output to the trailer
brakes.
Trailer Brake DIC Display Page
The ITBC system displays
messages on the vehicle’s Driver
Information Center (DIC). See
Driver Information Center (DIC) on
page 5‑28
for more information.
The display page indicates Trailer
Gain setting, power output to the
electric trailer brakes, trailer
connection, and system operational
status.
The Trailer Brake Display Page can
be displayed by performing any of
the following actions:
.Scrolling through the DIC menu
pages using the odometer trip
stem or the DIC Vehicle
Information button (if equipped).
.Pressing a Trailer Gain button—
If the Trailer Brake Display Page
is not currently displayed,
pressing a Trailer Gain button
will first recall the current Trailer
Gain setting. After the Trailer
Brake Display Page is displayed,
each press and release of the
gain buttons will then cause the
Trailer Gain setting to change.
.Activating the Manual Trailer
Brake Apply lever.
.Connecting a trailer equipped
with electric trailer brakes.
All DIC warning and service
messages must first be
acknowledged by the driver by
pressing the odometer trip stem or
the DIC Vehicle Information button
(if equipped) before the Trailer
Brake Display Page can be
displayed and Trailer Gain can be
adjusted.
TRAILER GAIN: This setting is
displayed any time the Trailer
Brake Display Page is active. This
setting can be adjusted from 0.0 to

Black plate (97,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
Driving and Operating 9-97
10.0 with either a trailer connected
or disconnected. To adjust the
Trailer Gain, press one of the Trailer
Gain adjustment buttons located on
the Trailer Brake Control Panel.
Press and hold a gain button to
cause the Trailer Gain to
continuously adjust. To turn the
output to the trailer off, adjust the
Trailer Gain setting to 0.0 (zero).
0.0 (zero) gain is the factory default
setting. To properly adjust trailer
gain, see“Trailer Gain Adjustment
Procedure” later in this section.
TRAILER OUTPUT: This is
displayed any time a trailer with
electric brakes is connected. Output
to the electric brakes is based on
the amount of vehicle braking
present and relative to the Trailer
Gain setting. Output is displayed
from 0 to 10 bars for each gain
setting.
Non-hybrid vehicles with Trailer
Sway Control (TSC) or Hill Start
Assist (HSA), output to the electric
trailer brakes may be displayed when the systems are active. See
Trailer Sway Control (TSC) on
page 9‑100
andHill Start Assist
(HSA) on page 9‑52.
The Trailer Output will indicate “- - -
- - -” on the Trailer Brake Display
Page whenever the following occur:
.No trailer is connected
.A trailer without electric brakes
is connected (no DIC message
is displayed)
.A trailer with electric brakes has
become disconnected (a
CHECK TRAILER WIRING
message will also be displayed
on the DIC)
.There is a fault present in the
wiring to the electric trailer
brakes (a CHECK TRAILER
WIRING message will also be
displayed on the DIC)
.There is a fault in the ITBC
system (a SERVICE TRAILER
BRAKE SYSTEM message will
also be displayed in the DIC) Manual Trailer Brake Apply
The Manual Trailer Brake Apply
Lever is located on the Trailer Brake
Control Panel and is used to apply
the trailer
’s electric brakes
independent of the vehicle’s brakes.
This lever is used in the Trailer Gain
Adjustment Procedure to properly
adjust the power output to the trailer
brakes. Sliding the lever to the left
will apply only the trailer brakes.
The power output to the trailer is
indicated in the Trailer Brake
Display Page on the DIC. If the
vehicle’s service brakes are applied
while using the Manual Trailer Brake
Apply Lever, the trailer output power
will be the greater of the two.
The trailer's and the vehicle's brake
lamps will come on when either
vehicle braking or manual trailer
brakes are applied.