Page 43 of 556

Black plate (37,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
In Brief 1-37
As the owner of a new GMC, you
are automatically enrolled in the
Roadside Assistance program.
SeeRoadside Assistance Program
(U.S. and Canada) on page 13‑7 or
Roadside Assistance Program
(Mexico) on page 13‑9.
Roadside Assistance and OnStar
(U.S. and Canada)
If you have an active OnStar
subscription, press the
Qbutton
and the current GPS location will
be sent to an OnStar advisor who
will assess your problem, contact
Roadside Assistance, and relay
your exact location to get the help
you need. Online Owner Center (U.S. and
Canada)
The Online Owner Center is a
complimentary service that includes
online service reminders, vehicle
maintenance tips, online owner
manual, special privileges,
and more.
Sign up today at:
U.S.: gmc.com (click on
“Owners,”
then“Manage My
GMC/Owners Login”)
Canada: gmcowner.ca
OnStar®
If equipped, this vehicle has a
comprehensive, in-vehicle system
that can connect to a live Advisor
for Emergency, Security, Navigation,
Connection, and Diagnostic
Services. See OnStar Overview on
page 14‑1.
Page 371 of 556

Black plate (95,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-95
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 specified in the trailering
chart for the vehicle. See“Weight of
the Trailer” underTrailer Towing on
page 9‑78 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.
Page 433 of 556

Black plate (47,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-47
FusesUsage
51 Heated Mirrors
52 SEO B1 Upfitter Usage
(Battery)
53 Accessory 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
60 Cooling Fan 2
61 Antilock Brake
System 1 J-Case
Fuses Usage
62 Starter
63 Stud 2 (Trailer Brakes)
64 Left Bussed Electrical
Center 1
65 Not Used
66 Not Used
67 Transfer Case
68 Stud 1 (Trailer
Connector
Battery Power)
(Optional - 40A Fuse
Required)
69 Mid-Bussed Electrical
Center 1
70 Climate Control Blower
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
REAR
DEFOG Rear Defogger
RUN/CRNK Switched Power
Page 434 of 556
Black plate (48,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-48 Vehicle Care
Instrument Panel Fuse
Block
The instrument panel fuse block
access door is located on the driver
side edge of the instrument panel.
Pull off the cover to access the fuse
block.
The vehicle may not be equipped
with all of the fuses, relays, and
features shown.Fuses Usage
1 Rear Seats
2 Rear Accessory
Power Outlet Fuses Usage
3 Steering Wheel
Controls Backlight
4 Driver Door Module
5 Dome Lamps, Driver
Side Turn Signal