GMC SIERRA 1500 2009 Owners Manual

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.
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.
Trailering may be limited by the vehicle’s ability to carry
tongue weight. Tongue weight cannot cause the
vehicle to exceed the GVWR (Gross Vehicle Weight
Rating) or the RGAWR (Rear Gross Axle Weight
Rating). The effect of additional weight may reduce the
trailering capacity more than the total of the additional
weight.Consider the following example:
A vehicle model base weight is 5,500 lbs (2 495 kg);
2,800 lbs (1 270 kg) at the front axle and 2,700 lbs
(1 225 kg) at the rear axle. It has a GVWR of 7,200 lbs
(3 266 kg), a RGAWR of 4,000 lbs (1 814 kg) and a
GCWR (Gross Combination Weight Rating) of
14,000 lbs (6 350 kg). The trailer rating should be:
Expect tongue weight to be at least 10 percent of trailer
weight (850 lbs (386 kg)) and because the weight is
applied well behind the rear axle, the effect on the rear
axle is greater than just the weight itself, as much
as 1.5 times as much. The weight at the rear axle could
be 850 lbs (386 kg) X 1.5 = 1,275 lbs (578 kg). Since
the rear axle already weighs 2,700 lbs (1 225 kg),
adding 1,275 lbs (578 kg) brings the total to 3,975 lbs
(1 803 kg). This is very close to, but within the limit
for RGAWR as well. The vehicle is set to trailer up to
8,500 lbs (3 856 kg).
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If the vehicle has many options and there is a front seat
passenger and two rear seat passengers with some
luggage and gear in the vehicle as well. 300 lbs (136 kg)
could be added to the front axle weight and 400 lbs
(181 kg) to the rear axle weight. The vehicle now weighs:
Weight is still below 7,200 lbs (3 266 kg) and you might
think 700 additional pounds (318 kg) should be
subtracted from the trailering capacity to stay within
GCWR limits. The maximum trailer would only be
7,800 lbs (3 538 kg). You may go further and think the
tongue weight should be limited to less than 1,000 lbs
(454 kg) to avoid exceeding GVWR. But the effect on the
rear axle must still be considered. Because the rear axle
now weighs 3,100 lbs (1 406 kg), 900 lbs (408 kg) can be
put on the rear axle without exceeding RGAWR. The
effect of tongue weight is about 1.5 times the actual
weight. Dividing the 900 lbs (408 kg) by 1.5 leaves only
600 lbs (272 kg) of tongue weight that can be handled.Since tongue weight is usually at least 10 percent of total
loaded trailer weight, expect that the largest trailer the
vehicle can properly handle is 6,000 lbs (2 721 kg).
It is important that the vehicle does not exceed any of
its ratings — GCWR, GVWR, RGAWR, Maximum Trailer
Rating or Tongue Weight. The only way to be sure it
is not exceeding any of these ratings is to weigh
the vehicle and trailer.
Total Weight on the Vehicle’s Tires
Be sure the vehicle’s tires are inated to the upper limit
for cold tires. These numbers can be found on the
Certication label at the rear edge of the drivers door or
seeLoading the Vehicle on page 4-34for more
information. Make sure not to go over the GVW limit for
the vehicle, or the GAWR, including the weight of the
trailer tongue. If using a weight distributing hitch,
make sure not to go over the rear axle limit before
applying the weight distribution spring bars.
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Hitches
It is important to have the correct hitch equipment.
Crosswinds, large trucks going by and rough roads are
a few reasons why the right hitch is needed.
Weight-Distributing Hitches and Weight
Carrying Hitches
A:Body to Ground Distance
B:Front of VehicleWhen using a weight-distributing hitch, the hitch must
be adjusted so the distance (A) remains the same both
before and after coupling the trailer to the tow vehicle.
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.
If the loaded trailer being pulled will weigh more than
5,000 lbs (2 270 kg), be sure to use a properly mounted
weight-distributing hitch and sway control of the proper
size. This equipment is very important for proper vehicle
loading and good handling when driving. Always use a
sway control if the trailer will weigh more than these
limits. Ask a hitch dealer about sway controls.
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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 to
25 percent of the trailer weight up to the maximum
amount specied in the trailering chart for the vehicle.
See “Weight of the Trailer” in this section 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
fth 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 5,000 lbs (2 271 kg)
with a factory-installed step bumper, safety chains
may be attached to the attaching points on the bumper.
If the trailer being towed weighs up to the vehicle’s
trailer rating limit, safety chains may be attached to the
attaching point on the hitch platform. Always leave
just enough slack so the rig can turn. Never allow safety
chains to drag on the ground.
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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 2-34for 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” later in the section.
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 benet 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.
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Trailer Brakes
A loaded trailer that weighs more than 2,000 lbs
(900 kg) 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.
If the vehicle is equipped with StabiliTrak
®, the
trailer cannot tap into the vehicle’s hydraulic brake
system.
The trailer brake system can tap into the vehicle’s
hydraulic brake system only if:
The trailer parts can withstand 3,000 psi
(20 650 kPa) of pressure.
The trailer’s brake system will use less than
0.02 cubic inch (0.3 cc) of uid from the vehicle’s
master cylinder. Otherwise, both braking systems
will not work well or at all.
If everything checks out this far, make the brake tap at
the port on the master cylinder that sends the uid
to the rear brakes. Use only steel brake tubing to make
the tap.
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,
anti-lock brake and StabiliTrak (if equipped) systems.
In trailering conditions that cause the vehicle’s anti-lock
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 the StabiliTrak system.
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If the vehicle’s brake, anti-lock 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.
{CAUTION:
Connecting a trailer that is not compatible with the
ITBC 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. An aftermarket controller
may be available for use with trailers with surge, air
or electric-over-hydraulic trailer brake systems.
To determine the type of brakes on the trailer and
the availability of controllers, check with your trailer
manufacturer or dealer/retailer.When trailering, make sure of the following:
The ITBC system is used only with trailers that are
equipped with electric brakes.
All applicable local and federal laws and regulations
are followed.
All electrical and mechanical connections to the
trailer are made correctly.
The trailer’s brakes are in proper working condition.
The trailer and vehicle are properly loaded for
the towing condition.
The ITBC system is a factory installed item.
Out-of-factory installation of this system should not be
attempted. GM is not responsible for warranty or
performance of the system resulting from out-of-factory
installation.
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Trailer Brake Control Panel
A. Manual Trailer Brake Apply Lever
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 Overview (Base/Uplevel version)
on page 3-4orInstrument Panel Overview (Premium
version) on page 3-6for more information on location.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 into the vehicle’s
Driver Information Center (DIC). SeeDIC Warnings
and Messages on page 3-66for more information.
The display page indicates Trailer Gain setting, power
output to the electric trailer brakes, trailer connection
and system operational status.
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A. Trailer Gain Setting
B. Power Output to Trailer Brakes
C. No trailer with electric brakes connected or fault
present
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 rst 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 rst 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 anytime the
Trailer Brake Display Page is active. This setting
can be adjusted from 0.0 to 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 the 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.
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The Trailer Output will indicate “------’’ontheTrailer
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 in 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 and the vehicle’s brake lamps will come on
when either vehicle braking or manual trailer brakes are
applied.
Trailer Gain Adjustment Procedure
Trailer Gain should be set for a specic 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 are in proper working
condition.
2. Connect a properly loaded trailer to the vehicle and
make all necessary mechanical and electrical
connections. SeeLoading the Vehicle on page 4-34
for more information.
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