towing GMC SIERRA 1500 2013 Service Manual

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 (92,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
9-92 Driving and Operating
exceeds the maximum amperage
rating of 40 amperes for the
auxiliary battery provision.
Trailer Wiring Harness
The vehicle is equipped with one of
the following wiring harnesses for
towing a trailer or hauling a slide-in
camper.
Basic Trailer Wiring
All regular, extended cab and crew
cab pickups have a seven-wire
trailer towing harness.
For vehicles not equipped with
heavy duty trailering, the harness is
secured to the vehicle's frame
behind the spare tire mount. The
harness requires the installation of a
trailer connector, which is available
through your dealer.
If towing a light-duty trailer with a
standard four-way round pin
connector, an adapter is available
from your dealer.Heavy-DutyTrailer Wiring Harness
Package
For vehicles equipped with heavy
duty trailering, the harness
connector is mounted in the bumper.
The seven-wire harness contains
the following trailer circuits:
.Yellow: Left Stop/Turn Signal
.Dark Green: Right Stop/Turn
Signal
.Brown: Taillamps
.White: Ground
.Light Green: Back-up Lamps
.Red: Battery Feed*
.Dark Blue: Trailer Brake*
*The fuses for these two circuits are
installed in the underhood electrical
center, but the wires are not
connected. They should be
connected by your dealer or a
qualified service center. The fuse
and wire for the ITBC is factory
installed and connected if the
vehicle is equipped with an ITBC.
The fuse for the battery feed is not
required if the vehicle has an
auxiliary battery. If the vehicle does
not have an auxiliary battery, have
your dealer or authorized service
center install the required fuse.
If charging a remote (non-vehicle)
battery, press the Tow/Haul Mode
button, if equipped, located at the
end of the shift lever. This will boost
the vehicle system voltage and
properly charge the battery. If the
trailer is too light for Tow/Haul
Mode, or the vehicle is not equipped
with Tow/Haul, turn on the

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 (98,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
9-98 Driving and Operating
Trailer Gain Adjustment Procedure
Trailer Gain should be set for a
specific trailering condition and must
be adjusted any time vehicle
loading, trailer loading, or road
surface conditions change.
Setting the Trailer Gain properly is
needed for the best trailer stopping
performance. A trailer that is
over-gained may result in locked
trailer brakes. A trailer that is
under-gained may result in not
enough trailer braking. Both of these
conditions may result in poorer
stopping and stability of the vehicle
and trailer.
Use the following procedure to
correctly adjust Trailer Gain for each
towing condition:
1. Make sure the trailer brakes arein proper working condition.
2. Connect a properly loaded trailer to the vehicle and make all
necessary mechanical and electrical connections. See
Vehicle Load Limits on
page 9‑15
for more information.
3. After the electrical connection is made to a trailer equipped with
electric brakes:
.A TRAILER CONNECTED
message will be briefly
displayed on the DIC.
.The Trailer Brake Display
Page will appear on the
DIC showing TRAILER
GAIN and TRAILER
OUTPUT.
.In the Trailer Output display
on the DIC, “- - - - - -”will
disappear if there is no
error present. Connecting a
trailer without electric
brakes will not clear the six
dashed lines.
4. Adjust the Trailer Gain by using the gain adjustment (+ / -)
buttons on the Trailer Brake
Control Panel. 5. Drive the vehicle with the trailer
attached on a level road surface
representative of the towing
condition and free of traffic at
about 32 to 40 km/h (20 to
25 mph) and fully apply the
Manual Trailer Brake Apply
Lever.
Adjusting trailer gain at speeds
lower than 32 to 40 km/h (20 to
25 mph) may result in an
incorrect gain setting.
6. Adjust the Trailer Gain to just below the point of trailer wheel
lock-up, indicated by trailer
wheel squeal or tire smoke when
a trailer wheel locks.
Trailer wheel lock-up may not
occur if towing a heavily loaded
trailer. In this case, adjust the
Trailer Gain to the highest
allowable setting for the towing
condition.

Black plate (99,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
Driving and Operating 9-99
7. Re-adjust Trailer Gain any timevehicle loading, trailer loading or
road surface conditions change
or if trailer wheel lock-up is
noticed at any time while towing.
Other ITBC-Related DIC Messages
In addition to displaying TRAILER
GAIN and TRAILER OUTPUT
through the DIC, trailer connection
and ITBC system status are
displayed on the DIC.
TRAILER CONNECTED: This
message will be briefly displayed
when a trailer with electric brakes is
first connected to the vehicle. This
message will automatically turn off
in about 10 seconds. The driver can
also acknowledge this message
before it automatically turns off. CHECK TRAILER WIRING: This
message will be displayed if:
1. The ITBC system first
determines connection to a
trailer with electric brakes and
then the trailer harness becomes
disconnected from the vehicle.
If the disconnect occurs while
the vehicle is stationary, this
message will automatically turn
off in about 30 seconds. This
message will also turn off if the
driver acknowledges this
message or if the trailer harness
is re-connected.
If the disconnect occurs while
the vehicle is moving, this
message will continue until the
ignition is turned off. This
message will also turn off if the
driver acknowledges this
message or if the trailer harness
is re-connected. 2. There is an electrical fault in the
wiring to the electric trailer
brakes. This message will
continue as long as there is an
electrical fault in the trailer
wiring. This message will also
turn off if the driver
acknowledges this message.
To determine if the electrical fault is
on the vehicle side or trailer side of
the trailer wiring harness
connection, do the following:
1. Disconnect the trailer wiring harness from the vehicle.
2. Turn the ignition off.
3. Wait 10 seconds, then turn the ignition back to RUN.
4. If the CHECK TRAILER WIRING message re-appears, the
electrical fault is on the
vehicle side.

Black plate (100,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
9-100 Driving and Operating
If the CHECK TRAILER WIRING
message only re-appears when
connecting the trailer wiring
harness to the vehicle, the
electrical fault is on the
trailer side.
SERVICE TRAILER BRAKE
SYSTEM: This message will be
displayed when there is a problem
with the ITBC system. If this
message persists over multiple
ignition cycles, there is a problem
with the ITBC system. Take the
vehicle to an authorized GM dealer
to have the ITBC system diagnosed
and repaired.
If either the CHECK TRAILER
WIRING or SERVICE TRAILER
BRAKE SYSTEM message is
displayed while driving the vehicle, power is no longer available to the
trailer brakes. When traffic
conditions allow, carefully pull the
vehicle over to the side of the road
and turn the ignition off. Check the
wiring connection to the trailer and
turn the ignition back on. If either of
these messages continues, either
the vehicle or trailer needs service.
An authorized GM dealer may be
able to diagnose and repair
problems with the trailer. However,
any diagnosis and repair of the
trailer is not covered under the
vehicle warranty. Please contact
your trailer dealer for assistance
with trailer repairs and trailer
warranty information.Trailer Sway
Control (TSC)
Non-hybrid vehicles with StabiliTrak
have a Trailer Sway Control (TSC)
feature. If the vehicle is towing a
trailer and the system detects that
the trailer is swaying, the vehicle
brakes are applied without the driver
pressing the brake pedal. If the
vehicle is equipped with the
Integrated Trailer Brake Control
(ITBC) system, StabiliTrak may also
apply the trailer brakes. The TCS/
StabiliTrak warning light will flash on
the instrument panel cluster to notify
the driver to reduce speed. If the
trailer continues to sway, StabiliTrak
will reduce engine torque to help
slow the vehicle. See
StabiliTrak
®
System on page 9‑53 for more
information.
Adding non‐dealer accessories can
affect the vehicle performance. See
Accessories and Modifications on
page 10‑3 for more information.

Black plate (2,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
10-2 Vehicle Care
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . 10-46
All-Season Tires . . . . . . . . . . . . 10-47
Winter Tires . . . . . . . . . . . . . . . . 10-48
Summer Tires . . . . . . . . . . . . . . 10-48
Tire Sidewall Labeling . . . . . . 10-48
Tire Designations . . . . . . . . . . . 10-51
Tire Terminology andDefinitions . . . . . . . . . . . . . . . . 10-52
Tire Pressure . . . . . . . . . . . . . . . 10-55
Tire Pressure for High-Speed Operation . . . . . . . . . . . . . . . . . 10-56
Tire Pressure Monitor System . . . . . . . . . . . . . . . . . . . 10-57
Tire Pressure Monitor Operation . . . . . . . . . . . . . . . . . 10-58
Tire Inspection . . . . . . . . . . . . . . 10-61
Tire Rotation . . . . . . . . . . . . . . . 10-61
Dual Tire Rotation . . . . . . . . . . 10-63
When It Is Time for New Tires . . . . . . . . . . . . . . . . . . . . . . 10-64
Buying New Tires . . . . . . . . . . . 10-65
Different Size Tires and Wheels . . . . . . . . . . . . . . . . . . . 10-66 Uniform Tire Quality
Grading . . . . . . . . . . . . . . . . . . . 10-67
Wheel Alignment and Tire Balance . . . . . . . . . . . . . . . . . . . 10-68
Wheel Replacement . . . . . . . . 10-69
Tire Chains . . . . . . . . . . . . . . . . . 10-70
If a Tire Goes Flat . . . . . . . . . . 10-70
Tire Changing . . . . . . . . . . . . . . 10-72
Full-Size Spare Tire . . . . . . . . 10-82
Jump Starting
Jump Starting . . . . . . . . . . . . . . 10-82
Towing
Towing the Vehicle . . . . . . . . . 10-87
Recreational Vehicle
Towing . . . . . . . . . . . . . . . . . . . . 10-87
Appearance Care
Exterior Care . . . . . . . . . . . . . . . 10-91
Interior Care . . . . . . . . . . . . . . . . 10-94
Floor Mats . . . . . . . . . . . . . . . . . . 10-97
General Information
For service and parts needs, visit
your dealer. You will receive
genuine GM parts and GM-trained
and supported service people.
Genuine GM parts have one of
these marks:
California Proposition
65 Warning
Most motor vehicles, including this
one, contain and/or emit chemicals
known to the State of California to

Black plate (21,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
Vehicle Care 10-21
Notice:Running the engine
without coolant may cause
damage or a fire. Vehicle damage
would not be covered by the
warranty. See Overheated Engine
Protection Operating Mode on
page 10‑22 for information on
driving to a safe place in an
emergency.
If Steam is Coming from the
Engine Compartment
{WARNING
Steam from an overheated engine
can burn you badly, even if you
just open the hood. Stay away
from the engine if you see or hear
steam coming from it. Turn it off
and get everyone away from the
vehicle until it cools down. Wait
until there is no sign of steam or
coolant before you open
the hood.
(Continued)
WARNING (Continued)
If you keep driving when the
vehicles engine is overheated,
the liquids in it can catch fire. You
or others could be badly burned.
Stop the engine if it overheats,
and get out of the vehicle until the
engine is cool.
SeeOverheated Engine
Protection Operating Mode on
page 10‑22 for information on
driving to a safe place in an
emergency.
If No Steam is Coming from
the Engine Compartment
The ENGINE OVERHEATED STOP
ENGINE or the ENGINE
OVERHEATED IDLE ENGINE
message, along with a low coolant
condition, can indicate a serious
problem. If there is an engine overheat
warning, but no steam is 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
Trailer Towing
on page 9‑73.
If the ENGINE OVERHEATED
STOP ENGINE or the ENGINE
OVERHEATED IDLE ENGINE
message appears with no sign of
steam, try this for a minute or so:
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. If stopped in a traffic jam, apply the brake, shift to N (Neutral);
otherwise, shift to the highest
gear while driving —D (Drive) or
3 (Third).

Black plate (22,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
10-22 Vehicle Care
If the temperature overheat 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.
If the warning continues, pull over,
stop, and park the vehicle
right away.
If there is no sign of steam, idle the
engine for five minutes while
parked. If the warning is still
displayed, turn off the engine until it
cools down. Also, see“Overheated
Engine Protection Operating Mode”
later in this section.
Overheated Engine
Protection
Operating Mode
If an overheated engine condition
exists and the ENGINE POWER IS
REDUCED message displays, an overheat protection mode which
alternates firing groups of cylinders
helps to prevent engine damage. In
this mode, a loss in power and
engine performance will be noticed.
This operating mode allows the
vehicle to be driven to a safe place
in an emergency. Driving
extended km (mi) and/or towing a
trailer in the overheat protection
mode should be avoided.
Notice:
After driving in the
overheated engine protection
operating mode, to avoid engine
damage, allow the engine to cool
before attempting any repair. The
engine oil will be severely
degraded. Repair the cause of
coolant loss, change the oil and
reset the oil life system. See
Engine Oil on page 10‑6.
Engine Fan
If 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 disengages.
This fan noise may also be heard
when starting the engine. It will go
away as the fan clutch partially
disengages.
If the vehicle has electric cooling
fans, the fans may be heard
spinning at low speed during most
everyday driving. The fans may turn
off if no cooling is required. Under
heavy vehicle loading, trailer towing,
high outside temperatures,

Black plate (87,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
Vehicle Care 10-87
Towing
Towing the Vehicle
Notice:Incorrectly towing a
disabled vehicle may cause
damage. The damage would not
be covered by the vehicle
warranty.
Have the vehicle towed on a flatbed
car carrier or a wheel lift tow truck.
If a wheel lift tow truck is used, the
drive wheels cannot contact the
road while the vehicle is being
towed. A wheel dolly must be used
to lift all drive wheels off the ground.
Consult your dealer or a
professional towing service if the
disabled vehicle must be towed.
To tow the vehicle behind another
vehicle for recreational purposes,
such as behind a motor home, see
“Recreational Vehicle Towing” in this
section.
Recreational Vehicle
Towing
Recreational vehicle towing means
towing the vehicle behind another
vehicle, such as 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:
.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
travelled? 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.
.Is the vehicle ready to be
towed? Just as preparing the
vehicle for a long trip, make sure
the vehicle is prepared to be
towed.
Dinghy Towing
Two-Wheel-Drive Vehicles