
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 (93,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
Driving and Operating 9-93
headlamps as a second way to
boost the vehicle system and
charge the battery.
Camper/Fifth-Wheel Trailer Wiring
Package
The seven-wire camper harness is
located under the front edge of the
pickup box on the driver side of the
vehicle, attached to the frame
bracket. A connector must be added
to the wiring harness which
connects to the camper.
The harness contains the following
camper/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
If the vehicle is equipped with the
“Heavy-Duty Trailering”option,
please refer to “Heavy-Duty Trailer
Wiring Package” earlier in this
section.
When the camper-wiring harness is
ordered without the heavy-duty
trailering package, a seven-wire
harness with a seven-pin connector
is located at the rear of the vehicle
and is tied to the vehicle's frame.
Electric Brake Control Wiring
Provisions
These wiring provisions are
included with the vehicle as part of
the trailer wiring package. These
provisions are for an electric brake
controller. The instrument panel
contains blunt cut wires behind the
steering column for the trailer brake
controller. The harness contains the
following wires:
.Dark Blue: Brake Signal to
Trailer Connector
.Red/Black: Battery
.Light Blue/White: Brake Switch
.White: Ground
The harness should be installed by
your dealer or a qualified service
center.
If the vehicle is equipped with an
Integrated Trailer Brake Control
(ITBC) System, the blunt cuts exist,
but are not connected further in the
harness. If an aftermarket trailer
brake controller is installed, the

Black plate (1,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
Vehicle Care 10-1
Vehicle Care
General Information
General Information . . . . . . . . . . 10-2
California Proposition65 Warning . . . . . . . . . . . . . . . . . 10-2
California Perchlorate Materials Requirements . . . . 10-3
Accessories and Modifications . . . . . . . . . . . . . . . 10-3
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 10-3
Hood . . . . . . . . . . . . . . . . . . . . . . . . 10-4
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . 10-5
Engine Oil . . . . . . . . . . . . . . . . . . . 10-6
Engine Oil Life System . . . . . . 10-9
Automatic Transmission Fluid (4-Speed
Transmission) . . . . . . . . . . . . . 10-10
Automatic Transmission Fluid (6-Speed
Transmission) . . . . . . . . . . . . . 10-12
Engine Air Cleaner/Filter . . . . 10-15
Cooling System . . . . . . . . . . . . 10-16
Engine Coolant . . . . . . . . . . . . . 10-17 Engine Overheating . . . . . . . . 10-20
Overheated Engine
Protection
Operating Mode . . . . . . . . . . . 10-22
Engine Fan . . . . . . . . . . . . . . . . . 10-22
Power Steering Fluid . . . . . . . 10-23
Washer Fluid . . . . . . . . . . . . . . . 10-23
Brakes . . . . . . . . . . . . . . . . . . . . . 10-24
Brake Fluid . . . . . . . . . . . . . . . . . 10-25
Battery . . . . . . . . . . . . . . . . . . . . . 10-27
Four-Wheel Drive . . . . . . . . . . . 10-28
Front Axle . . . . . . . . . . . . . . . . . . 10-29
Rear Axle . . . . . . . . . . . . . . . . . . 10-30
Noise Control System . . . . . . 10-31
Starter Switch Check . . . . . . . 10-32
Automatic Transmission Shift
Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . 10-32
Ignition Transmission Lock Check . . . . . . . . . . . . . . . . . . . . . 10-32
Park Brake and P (Park) Mechanism Check . . . . . . . . 10-33
Wiper Blade Replacement . . . . . . . . . . . . . . 10-33
Glass Replacement . . . . . . . . 10-34
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . 10-34
Bulb Replacement
Bulb Replacement . . . . . . . . . . 10-34
Halogen Bulbs . . . . . . . . . . . . . . 10-34
Headlamps, Front Turn Signal, Sidemarker, and
Parking Lamps . . . . . . . . . . . . 10-35
Pick-Up Box Identification and Fender Marker
Lamps . . . . . . . . . . . . . . . . . . . . 10-35
Taillamps (Chassis Cab Models) . . . . . . . . . . . . . . . . . . . 10-36
Taillamps, Turn Signal, Stoplamps, and Back-Up
Lamps . . . . . . . . . . . . . . . . . . . . 10-36
Center High-Mounted Stoplamp (CHMSL) and
Cargo Lamp . . . . . . . . . . . . . . 10-37
License Plate Lamp . . . . . . . . 10-37
Replacement Bulbs . . . . . . . . . 10-38
Electrical System
Electrical System Overload . . . . . . . . . . . . . . . . . . 10-38
Fuses and Circuit Breakers . . . . . . . . . . . . . . . . . . 10-39
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . 10-39
Instrument Panel Fuse Block . . . . . . . . . . . . . . . . . . . . . 10-43

Black plate (38,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
10-38 Vehicle Care
3. Turn the bulb socket (C) one‐quarter turn to release the bulb
socket from the lamp
housing (A).
4. Pull the bulb (B) from the bulb socket (C).
5. Reverse the steps to install.
Replacement Bulbs
Exterior Lamp Bulb Number
Back-up Lamp 3047K
Back-up Lamp* 1156
Cargo Lamp and
Center
High-Mounted
Stoplamp
(CHMSL) 912
Fender Marker W5WLL
Front Turn Signal
Lamp, Sidemarker
Lamp, and
Parking Lamp 3157AExterior Lamp Bulb
Number
High-Beam
Headlamp 9005
Low-Beam
Headlamp H11
License
Plate Lamp 168
Stoplamp/Taillamp/
Turn Signal Lamp 3047K
Sidemarker Lamp 194
Stoplamp/Turn
Signal Lamp/
Taillamp* 1157
* Chassis Cab Models
For replacement bulbs not listed
here, contact your dealer.
Electrical System
Electrical System
Overload
The vehicle has fuses and circuit
breakers to protect against an
electrical system overload.
When the current electrical load is
too heavy, the circuit breaker opens
and closes, protecting the circuit
until the current load returns to
normal or the problem is fixed. This
greatly reduces the chance of circuit
overload and fire caused by
electrical problems.
Fuses and circuit breakers protect
power devices in the vehicle.
Replace a bad fuse with a new one
of the identical size and rating.
If there is a problem on the road and
a fuse needs to be replaced, the
same amperage fuse can be
borrowed. Choose some feature of
the vehicle that is not needed to use
and replace it as soon as possible.

Black plate (39,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
Vehicle Care 10-39
Headlamp Wiring
An electrical overload may cause
the lamps to go on and off, or in
some cases to remain off. Have the
headlamp wiring checked right away
if the lamps go on and off or
remain off.
Windshield Wipers
If the wiper motor overheats due to
heavy snow or ice, the windshield
wipers will stop until the motor cools
and will then restart.
Although the circuit is protected
from electrical overload, overload
due to heavy snow or ice may
cause wiper linkage damage.
Always clear ice and heavy snow
from the windshield before using the
windshield wipers.
If the overload is caused by an
electrical problem and not snow or
ice, be sure to get it fixed.
Fuses and Circuit
Breakers
If the vehicle is a hybrid, see the
hybrid supplement for more
information.
The wiring circuits in the vehicle are
protected from short circuits by a
combination of fuses, circuit
breakers and fusible thermal links.
This greatly reduces the chance of
fires caused by electrical problems.
Look at the silver-colored band
inside the fuse. If the band is broken
or melted, replace the fuse. Be sure
you replace a bad fuse with a new
one of the identical size and rating.
If you ever have a problem on the
road and don't have a spare fuse,
you can borrow one that has the
same amperage. Just pick some
feature of your vehicle that you can
get along without–like the radio or
accessory power outlet– and use its
fuse, if it is the correct amperage.
Replace it as soon as you can.
Engine Compartment
Fuse Block
If the vehicle has a diesel engine,
see the Duramax Diesel supplement
for more information.
If the vehicle is a hybrid, see the
hybrid supplement for more
information.
The Engine Compartment Fuse
Block is located in the engine
compartment, on the driver side of
the vehicle.

Black plate (45,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
Vehicle Care 10-45
FusesUsage
17 Interior Lamps
18 Power Door Lock 1 (Unlock Feature)
19 Rear Seat Entertainment
20 Ultrasonic Rear Parking Assist, Power
Liftgate
21 Power Door Lock 1 (Lock Feature)
22 Driver Information Center (DIC)
23 Rear Wiper
24 Cooled Seats
25 Driver Seat Module, Remote Keyless Entry
System
26 Driver Power Door Lock (Unlock Feature) Circuit
Breaker Usage
LT DR Driver Side Power Window Circuit
Breaker
Harness
Connector Usage
LT DR Driver Door
Harness
Connection
BODY Harness Connector
BODY Harness Connector
Center Instrument Panel Fuse
Block
The center instrument panel fuse
block is located underneath the
instrument panel, to the left of the
steering column.
Top View
Harness
Connector Usage
BODY 2 Body Harness Connector 2
BODY 1 Body Harness Connector 1
BODY 3 Body Harness Connector 3
HEADLINER 3 Headliner Harness
Connector 3

Black plate (46,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
10-46 Vehicle Care
Harness
Connector Usage
HEADLINER 2 Headliner Harness
Connector 2
HEADLINER 1 Headliner Harness
Connector 1
SEO/
UPFITTER Special Equipment
Option Upfitter
Harness Connector
Circuit
Breaker Usage
CB1 Passenger Side Power Window Circuit
Breaker
CB2 Passenger Seat Circuit Breaker
CB3 Driver Seat Circuit Breaker
CB4 Rear Sliding WindowWheels and Tires
Tires
Every new GM vehicle has
high-quality tires made by a
leading tire manufacturer. See
the warranty manual for
information regarding the tire
warranty and where to get
service. For additional
information refer to the tire
manufacturer.
{WARNING
.Poorly maintained and
improperly used tires are
dangerous.
.Overloading the tires can
cause overheating as a
result of too much flexing.
There could be a blowout
(Continued)
WARNING (Continued)
and a serious crash. See
Vehicle Load Limits on
page 9‑15.
.Underinflated tires pose
the same danger as
overloaded tires. The
resulting crash could
cause serious injury.
Check all tires frequently
to maintain the
recommended pressure.
Tire pressure should be
checked when the tires
are cold.
.Overinflated tires are more
likely to be cut, punctured,
or broken by a sudden
impact— such as when
hitting a pothole. Keep
tires at the recommended
pressure.
(Continued)

Black plate (3,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
INDEX i-3
Charging System Light . . . . . . . . 5-20
CheckEngine Light . . . . . . . . . . . . . . . . . . 5-21
IgnitionTransmission Lock . . . . . . . . 10-32
Child Restraints Infants and Young
Children . . . . . . . . . . . . . . . . . . . . . 3-40
Lower Anchors and Tethers for Children . . . . . . . . . 3-45
Older Children . . . . . . . . . . . . . . . . 3-38
Securing . . . . . . . . . . 3-54, 3-56, 3-57
Systems . . . . . . . . . . . . . . . . . . . . . . 3-42
Cigarette Lighter . . . . . . . . . . . . . . . . 5-9
Circuit Breakers . . . . . . . . . . . . . . 10-39
Cleaning Exterior Care . . . . . . . . . . . . . . . 10-91
Interior Care . . . . . . . . . . . . . . . . 10-94
Climate Control Systems . . . 8-1, 8-4 Air Conditioning . . . . . . . . . . 8-1, 8-4
Dual Automatic . . . . . . . . . . . . . . . . 8-5
Heating . . . . . . . . . . . . . . . . . . . 8-1, 8-4
Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
Cluster, Instrument . . . . . . . . . . . . 5-11
Collision Damage Repair . . . . . 13-14
Compass . . . . . . . . . . . . . . . . . . . . . . . 5-5 Connections
OnStar®. . . . . . . . . . . . . . . . . . . . . . 14-3
Control of a Vehicle . . . . . . . . . . . . . 9-3
Convex Mirrors . . . . . . . . . . . . . . . . 2-13
Coolant Engine . . . . . . . . . . . . . . . . . . . . . . 10-17
Engine TemperatureGauge . . . . . . . . . . . . . . . . . . . . . . 5-15
Cooling System . . . . . . . . . . . . . . . 10-16 Engine Messages . . . . . . . . . . . . 5-39
Courtesy Transportation
Program . . . . . . . . . . . . . . . . . . . . . 13-13
Cruise Control . . . . . . . . . . . . . . . . . 9-56 Light . . . . . . . . . . . . . . . . . . . . . . . . . . 5-28
Cupholders . . . . . . . . . . . . . . . . . . . . . 4-1
Customer Assistance . . . . . . . . . . 13-6 Offices . . . . . . . . . . . . . . . . . . . . . . . . 13-5
Text Telephone (TTY)Users . . . . . . . . . . . . . . . . . . . . . . . 13-6
Customer Information Service Publications
Ordering Information . . . . . . 13-16
Customer Satisfaction Procedure . . . . . . . . . . . . . . 13-2, 13-4D
Damage Repair, Collision . . . . . 13-14
Danger, Warnings, andCautions . . . . . . . . . . . . . . . . . . . . . . . . iv
Data Recorders, Event . . . . . . . 13-19
Daytime Running Lamps (DRL) . . . . . . . . . . . . . . . . . . 6-3
Defensive Driving . . . . . . . . . . . . . . . 9-3
Delayed Locking . . . . . . . . . . . . . . . . 2-7
Devices Auxiliary . . . . . . . . . . . . . . . . . . . . . . 7-33
Diagnostics OnStar
®. . . . . . . . . . . . . . . . . . . . . . 14-5
Distracted Driving . . . . . . . . . . . . . . . 9-2
Dome Lamps . . . . . . . . . . . . . . . . . . . 6-7
Door Ajar Messages . . . . . . . . . . . . . . . 5-38
Delayed Locking . . . . . . . . . . . . . . . 2-7
Locks . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Power Locks . . . . . . . . . . . . . . . . . . . 2-7
Rear Doors . . . . . . . . . . . . . . . . . . . . 2-8
Drive Belt Routing, Engine . . . . . 12-6
Driver Information Center (DIC) . . . . . . . . . . . . . . . . . 5-28