trailer GMC SIERRA 2011 Repair Manual

Black plate (121,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-121
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. 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.

Black plate (122,1)GMC Sierra Owner Manual - 2011
9-122 Driving and Operating
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 9‑25 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.
7. Re-adjust Trailer Gain any time vehicle loading, trailer loading or
road surface conditions change
or if trailer wheel lock-up is
noticed at any time while towing.

Black plate (123,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-123
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 firstdetermines 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.
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.

Black plate (124,1)GMC Sierra Owner Manual - 2011
9-124 Driving and Operating
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)
Trailer Sway Control (TSC)
2500 and 3500 series 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's 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.
Adding non‐dealer accessories can
affect the vehicle's performance.
See
Accessories and Modifications
on page 10‑3 for more information.

Black plate (13,1)GMC Sierra Owner Manual - 2011
Vehicle Care 10-13
Automatic
Transmission Fluid
(4-Speed Transmission)
When to Check and Change
Automatic Transmission Fluid
A good time to check the automatic
transmission fluid level is when the
engine oil is changed.
Change the fluid and filter at
the intervals listed inScheduled
Maintenance on page 11‑2 and be
sure to use the transmission fluid
listed in Recommended Fluids and
Lubricants on page 11‑8.
How to Check Automatic
Transmission Fluid
Because this operation can be a
little difficult, it may be best to have
this done at the dealer service
department.
If not taken to the dealer, be sure to
follow all the instructions here or a
false reading on the dipstick could
result.
Notice: Too much or too
little fluid can damage the
transmission. Too much can
mean that some of the fluid could
come out and fall on hot engine
parts or exhaust system parts,
starting a fire. Too little fluid
could cause the transmission
to overheat. Be sure to get an
accurate reading if checking
the transmission fluid. Wait at least 30 minutes before
checking the transmission fluid
level if you have been driving:.When outside temperatures are
above 32°C (90°F).
.At high speed for quite a while.
.In heavy traffic
—especially in
hot weather.
.While pulling a trailer.
To get the right reading, the fluid
should be at normal operating
temperature, which is 82°C to 93°C
(180°F to 200°F).
Get the vehicle warmed up by
driving about 24 km (15 miles) when
outside temperatures are above
10°C (50°F). If it is colder than 10°C
(50°F), drive the vehicle in 3 (Third)
until the engine temperature gauge
moves and then remains steady for
10 minutes.

Black plate (27,1)GMC Sierra Owner Manual - 2011
Vehicle Care 10-27
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; seeTrailer Towing
on page 9‑95. 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).
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.

Black plate (28,1)GMC Sierra Owner Manual - 2011
10-28 Vehicle Care
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 10‑7.
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,
or operation of the air conditioning
system, the fans may change to
high speed and an increase in fan
noise may be heard. This is normal
and indicates that the cooling
system is functioning properly.
The fans will change to low speed
when additional cooling is no
longer required.

Black plate (51,1)GMC Sierra Owner Manual - 2011
Vehicle Care 10-51
FusesUsage
1 Right Trailer
Stop/Turn Lamp
2 Electronic
Suspension
Control, Automatic
Level Control
Exhaust Fuses
Usage
3 Left Trailer
Stop/Turn Lamp
4 Engine Controls
5 Engine Control
Module, Throttle
Control Fuses
Usage
6 Trailer Brake
Controller
7 Front Washer
8 Oxygen Sensor
9 Antilock Brakes
System 2
10 Trailer Back-up
Lamps
11 Driver Side
Low-Beam
Headlamp
12 Engine Control
Module (Battery)
13 Fuel Injectors,
Ignition Coils
(Right Side)
14 Transmission
Control Module
(Battery)
15 Vehicle Back-up
Lamps

Black plate (52,1)GMC Sierra Owner Manual - 2011
10-52 Vehicle Care
FusesUsage
16 Passenger Side
Low-Beam
Headlamp
17 Air Conditioning
Compressor
18 Oxygen Sensors
19 Transmission
Controls (Ignition)
20 Fuel Pump
21 Fuel System
Control Module
22 Not Used
23 Not Used
24 Fuel Injectors,
Ignition Coils
(Left Side)
25 Trailer Park Lamps
26 Driver Side Park
Lamps
27 Passenger Side
Park Lamps Fuses
Usage
28 Fog Lamps
29 Horn
30 Passenger Side
High-Beam
Headlamp
31 Daytime Running
Lamps (DRL)
32 Driver Side
High-Beam
Headlamp
33 Daytime Running
Lamps 2
34 Sunroof
35 Key Ignition
System, Theft
Deterrent System
36 Windshield Wiper
37 SEO B2 Upfitter
Usage (Battery)
38 Electric Adjustable
Pedals Fuses
Usage
39 Climate Controls
(Battery)
40 Airbag System
(Ignition)
41 Amplifier
42 Audio System
43 Miscellaneous
(Ignition),
Cruise Control
44 Not Used
45 Airbag System
(Battery)
46 Instrument Panel
Cluster
47 Power Take-Off
48 Auxiliary Climate
Control (Ignition)
49 Center
High-Mounted
Stoplamp (CHMSL)
50 Rear Defogger

Black plate (53,1)GMC Sierra Owner Manual - 2011
Vehicle Care 10-53
FusesUsage
51 Heated Mirrors
52 SEO B1 Upfitter
Usage (Battery)
53 Cigarette Lighter,
Auxiliary Power
Outlet
54 SEO Upfitter
Usage
55 Climate Controls
(Ignition)
56 Engine Control
Module, Secondary
Fuel Pump
(Ignition)
J-Case Fuses Usage
57 Cooling Fan 1
58 Not Used
59 Heavy Duty
Antilock Brake
System J-Case
Fuses Usage
60 Cooling Fan 2
61 Antilock Brake
System 1
62 Starter
63 Stud 2
(Trailer Brakes)
64 Left Bussed
Electrical Center 1
65 Not Used
66 Heated Windshield
Washer System
67 Transfer Case
68 Stud 1 (Trailer
Connector
Battery Power)
(Optional - 40A
Fuse Required)
69 Mid-Bussed
Electrical Center 1
70 Climate Control
Blower J-Case
Fuses Usage
71 Not Used
72 Left Bussed
Electrical Center 2
Relays Usage
FAN HI Cooling Fan High
Speed
FAN LO Cooling Fan Low
Speed
FAN CNTRL Cooling Fan
Control
HDLP
LO/HID Low-Beam
Headlamp
FOG LAMP Front Fog Lamps
A/C
CMPRSR Air Conditioning
Compressor
STRTR Starter
PWR/TRN Powertrain
FUEL PMP Fuel Pump
PRK LAMP Parking Lamps