light GMC SIERRA 1500 2012 Owners Manual

Black plate (38,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-38 Vehicle Care
Headlamp aiming is done with the
vehicle's low-beam headlamps.
The high-beam headlamps will be
correctly aimed if the low-beam
headlamps are aimed properly.
To adjust the vertical aim:
1. Open the hood. SeeHood on
page 10‑5
2. Locate the aim dot on the lens of the low‐beam headlamp.
3. Record the distance from the ground to the aim dot on the
low‐beam headlamp.
4. At a wall, measure from the
ground upward (A) to the
recorded distance from
Step 3 and mark it.
5. Draw or tape a horizontal line (B) on the wall the width of the
vehicle at the height of the mark
in Step 4.
Notice: Do not cover a headlamp
to improve beam cut-off when
aiming. Covering a headlamp may
cause excessive heat build-up
which may cause damage to the
headlamp. 6. Turn on the low-beam
headlamps and place a piece
of cardboard or equivalent in
front of the headlamp not being
adjusted. This allows only the
beam of light from the headlamp
being adjusted to be seen on the
flat surface.
7. Locate the vertical headlamp
aiming screws, which are under
the hood near each headlamp
assembly.
The adjustment screw can be
turned with an E8 Torx
®socket.

Black plate (39,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-39
8. Turn the vertical aiming screwuntil the headlamp beam is
aimed to the horizontal tape
line. Turn it clockwise or
counterclockwise to raise or
lower the angle of the beam.
9. Make sure that the light from theheadlamp is positioned at the
bottom edge of the horizontal
tape line. The lamp on the
left (A) shows the correct
headlamp aim. The lamp on the
right (B) shows the incorrect
headlamp aim.
10. Repeat Steps 7 through 9 for the opposite headlamp.
Bulb Replacement
For the proper type of replacement
bulbs, see Replacement Bulbs on
page 10‑43.
For any bulb‐changing procedure
not listed in this section, contact
your dealer.
Halogen Bulbs
{WARNING
Halogen bulbs have pressurized
gas inside and can burst if you
drop or scratch the bulb. You or
others could be injured. Be sure
to read and follow the instructions
on the bulb package.
Headlamps, Front Turn
Signal, Sidemarker, and
Parking Lamps
A. Side Marker Lamp
B. Low-Beam Headlamp
C. High-Beam Headlamp
D. Park/Turn Signal Lamp
1. Open the hood. See Hood on
page 10‑5
2. When replacing a driver side bulb on a vehicle with duel
batteries, see your dealer.

Black plate (40,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-40 Vehicle Care
3. When replacing a bulb on thepassenger side, remove the
Engine Air Cleaner cover. See
Engine Air Cleaner/Filter on
page 10‑17 for more information.
4. Reach in and access the bulb sockets from inside the engine
compartment.
5. Turn the bulb socket counterclockwise to remove it
from the headlamp assembly
and pull it straight out.
6. Unplug the electrical connector from the old bulb by releasing
the clips on the bulb socket.
7. Replace it with a new bulb.
8. Plug in the electrical connector.
9. Reinstall the new bulb socket into the headlamp assembly and
turn it clockwise to secure.Pick-Up Box Identification
and Fender Marker
Lamps
The pick-up box identification lamps
are LEDs. For replacement of the
LED lighting assembly contact your
dealer.
To replace a pickup box fender
marker lamp bulb:
1. Press the tab from the back toremove the lamp.
2. Turn the bulb socket counterclockwise to remove
from the lamp assembly.
3. Gently pry the bulb from the socket.
4. Install the new bulb in socket.
5. Reinstall socket into lamp assembly.
6. Reinstall the lamp assembly.
Taillamps (Chassis Cab
Models)
A. Backup Lamp
B. Stoplamp/Taillamp/Turn Signal Lamp
To replace one of these bulbs:
1. Remove the four screws.
2. Lift the lens off the lamp assembly.
3. Turn the old bulb counterclockwise and pull the
it straight out from the socket.

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

Black plate (49,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-49
FusesUsage
6 Driver Side Turn
Signal, Stoplamp
7 Instrument Panel
Back Lighting
8 Passenger Side Turn
Signal, Stoplamp
9 Passenger Door
Module, Driver Unlock
10 Power Door Lock 2
(Unlock Feature)
11 Power Door Lock 2
(Lock Feature)
12 Stoplamps, Center
High‐Mounted
Stoplamp
13 Rear Climate Controls
14 Power Mirror
15 Body Control
Module (BCM)
16 Accessory Power
Outlets Fuses
Usage
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.

Black plate (52,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-52 Vehicle Care
Tire Sidewall Labeling
Useful information about a tire
is molded into the sidewall.
The examples show a typical
passenger and light truck tire
sidewall.
Passenger (P‐Metric) Tire
(A) Tire Size:The tire size
code is a combination of letters
and numbers used to define a
particular tire's width, height,
aspect ratio, construction type, and service description. See
the
“Tire Size” illustration later
in this section for more detail.
(B) TPC Spec (Tire
Performance Criteria
Specification)
:Original
equipment tires designed to
GM's specific tire performance
criteria have a TPC specification
code molded onto the sidewall.
GM's TPC specifications meet
or exceed all federal safety
guidelines.
(C) DOT (Department of
Transportation)
:The
Department of Transportation
(DOT) code indicates that
the tire is in compliance
with the U.S. Department of
Transportation Motor Vehicle
Safety Standards. (D) Tire Identification Number
(TIN)
:The letters and numbers
following the DOT code are
the Tire Identification Number
(TIN). The TIN shows the
manufacturer and plant
code, tire size, and date the
tire was manufactured. The TIN
is molded onto both sides of the
tire, although only one side may
have the date of manufacture.
(E) Tire Ply Material
:The type
of cord and number of plies in
the sidewall and under the tread.
(F) Uniform Tire Quality
Grading (UTQG)
:Tire
manufacturers are required
to grade tires based on
three performance factors:
treadwear, traction, and
temperature resistance. For
more information, see Uniform
Tire Quality Grading on
page 10‑70.

Black plate (53,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-53
(G) Maximum Cold Inflation
Load Limit
:Maximum load
that can be carried and the
maximum pressure needed
to support that load. For
information on recommended
tire pressure see Tire Pressure
on page 10‑58 andVehicle Load
Limits on page 9‑16.
Light Truck (LT-Metric) Tire
(A) Tire Size:The tire size
code is a combination of letters
and numbers used to define a
particular tire's width, height, aspect ratio, construction type,
and service description. See the
“Tire Size”
illustration later in this
section for more detail.
(B) TPC Spec (Tire
Performance Criteria
Specification)
:Original
equipment tires designed to
GM's specific tire performance
criteria have a TPC specification
code molded onto the sidewall.
GM's TPC specifications meet
or exceed all federal safety
guidelines.
(C) Dual Tire Maximum Load
:
Maximum load that can be
carried and the maximum
pressure needed to support
that load when used in a dual
configuration. For information on
recommended tire pressure see
Tire Pressure on page 10‑58
and Vehicle Load Limits on
page 9‑16. (D) DOT (Department of
Transportation)
:The
Department of Transportation
(DOT) code indicates that
the tire is in compliance
with the U.S. Department of
Transportation Motor Vehicle
Safety Standards.
(E) Tire Identification Number
(TIN)
:The letters and numbers
following the DOT code are
the Tire Identification Number
(TIN). The TIN shows the
manufacturer and plant code,
tire size, and date the tire was
manufactured. The TIN is
molded onto both sides of the
tire, although only one side may
have the date of manufacture.

Black plate (54,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-54 Vehicle Care
(F) Tire Ply Material:The type
of cord and number of plies in
the sidewall and under the tread.
(G) Single Tire Maximum
Load
:Maximum load that can
be carried and the maximum
pressure needed to support that
load when used as a single. For
information on recommended
tire pressure see Tire Pressure
on page 10‑58 andVehicle Load
Limits on page 9‑16.
Tire Designations
Tire Size
The examples show a typical
passenger vehicle and light
truck tire size.
Passenger (P‐Metric) Tire
(A) Passenger (P‐Metric) Tire:
The United States version of a
metric tire sizing system. The
letter P as the first character in
the tire size means a passenger
vehicle tire engineered to
standards set by the U.S. Tire
and Rim Association.
(B) Tire Width
:The three‐digit
number indicates the tire section
width in millimeters from
sidewall to sidewall.
(C) Aspect Ratio
:A two‐digit
number that indicates the tire
height‐to‐width measurements.
For example, if the tire size
aspect ratio is 75, as shown in
item C of the tire illustration, it would mean that the tire's
sidewall is 75 percent as high
as it is wide.
(D) Construction Code
:A
letter code is used to indicate
the type of ply construction in
the tire. The letter R means
radial ply construction; the
letter D means diagonal or
bias ply construction; and the
letter B means belted‐bias ply
construction.
(E) Rim Diameter
:Diameter of
the wheel in inches.
(F) Service Description
:These
characters represent the load
index and speed rating of the
tire. The load index represents
the load carrying capacity a tire
is certified to carry. The speed
rating is the maximum speed a
tire is certified to carry a load.

Black plate (55,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-55
Light Truck (LT‐Metric) Tire
(A) Light Truck (LT‐Metric)
Tire
:The United States version
of a metric tire sizing system.
The letters LT as the first two
characters in the tire size mean
a light truck tire engineered to
standards set by the U.S. Tire
and Rim Association.
(B) Tire Width
:The three‐digit
number indicates the tire section
width in millimeters from
sidewall to sidewall.
(C) Aspect Ratio
:A two‐digit
number that indicates the tire
height‐to‐width measurements.
For example, if the tire size
aspect ratio is 75, as shown
in item C of the light truck (LT‐Metric) tire illustration, it
would mean that the tire's
sidewall is 75 percent as high
as it is wide.
(D) Construction Code
:A
letter code is used to indicate
the type of ply construction in
the tire. The letter R means
radial ply construction; the
letter D means diagonal or
bias ply construction; and the
letter B means belted‐bias ply
construction.
(E) Rim Diameter
:Diameter of
the wheel in inches.
(F) Load Range
:Load Range.
(G) Service Description
:The
service description indicates the
load index and speed rating of a
tire. If two numbers are given as
in the example, 120/116, then
this represents the load index for
single versus dual wheel usage (single/dual). The speed rating is
the maximum speed a tire is
certified to carry a load.
Tire Terminology and
Definitions
Air Pressure:The amount
of air inside the tire pressing
outward on each square inch
of the tire. Air pressure is
expressed in kPa (kilopascal)
or psi (pounds per square inch).
Accessory Weight
:The
combined weight of optional
accessories. Some examples
of optional accessories are
automatic transmission, power
steering, power brakes, power
windows, power seats, and air
conditioning.
Aspect Ratio
:The relationship
of a tire's height to its width.

Black plate (56,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-56 Vehicle Care
Belt:A rubber coated layer of
cords that is located between
the plies and the tread. Cords
may be made from steel or other
reinforcing materials.
Bead
:The tire bead contains
steel wires wrapped by steel
cords that hold the tire onto
the rim.
Bias Ply Tire
:A pneumatic tire
in which the plies are laid at
alternate angles less than
90 degrees to the centerline of
the tread.
Cold Tire Pressure
:The
amount of air pressure in a tire,
measured in kPa (kilopascal)
or psi (pounds per square inch)
before a tire has built up heat
from driving. See Tire Pressure
on page 10‑58. Curb Weight
:The weight of a
motor vehicle with standard and
optional equipment including the
maximum capacity of fuel,
oil, and coolant, but without
passengers and cargo.
DOT Markings
:A code molded
into the sidewall of a tire
signifying that the tire is in
compliance with the U.S.
Department of Transportation
(DOT) Motor Vehicle Safety
Standards. The DOT code
includes the Tire Identification
Number (TIN), an alphanumeric
designator which can also
identify the tire manufacturer,
production plant, brand, and
date of production.
GVWR
:Gross Vehicle Weight
Rating. See Vehicle Load Limits
on page 9‑16. GAWR FRT
:Gross Axle
Weight Rating for the front axle.
See Vehicle Load Limits on
page 9‑16.
GAWR RR
:Gross Axle Weight
Rating for the rear axle. See
Vehicle Load Limits on
page 9‑16.
Intended Outboard Sidewall
:
The side of an asymmetrical tire,
that must always face outward
when mounted on a vehicle.
Kilopascal (kPa)
:The metric
unit for air pressure.
Light Truck (LT‐Metric) Tire
:A
tire used on light duty trucks and
some multipurpose passenger
vehicles.
Load Index
:An assigned
number ranging from 1 to 279
that corresponds to the load
carrying capacity of a tire.