brake light GMC YUKON 2012 Owner's Guide

Black plate (26,1)GMC Yukon/Yukon XL Owner Manual - 2012
10-26 Vehicle Care
Brakes
This vehicle has disc brakes. Disc
brake pads have built-in wear
indicators that make a high-pitched
warning sound when the brake pads
are worn and new pads are needed.
The sound can come and go or be
heard all the time the vehicle is
moving, except when applying the
brake pedal firmly.
{WARNING
The brake wear warning sound
means that soon the brakes will
not work well. That could lead to
a crash. When the brake wear
warning sound is heard, have the
vehicle serviced.
Notice: Continuing to drive with
worn-out brake pads could result
in costly brake repair. Some driving conditions or climates
can cause a brake squeal when the
brakes are first applied or lightly
applied. This does not mean
something is wrong with the brakes.
Properly torqued wheel nuts are
necessary to help prevent brake
pulsation. When tires are rotated,
inspect brake pads for wear and
evenly tighten wheel nuts in the
proper sequence to torque
specifications in
Capacities and
Specifications on page 12‑2.
Brake linings should always be
replaced as complete axle sets.
Brake Pedal Travel
See your dealer if the brake pedal
does not return to normal height,
or if there is a rapid increase in
pedal travel. This could be a sign
that brake service might be
required.
Brake Adjustment
Every time the brakes are applied,
with or without the vehicle moving,
the brakes adjust for wear.
Replacing Brake System Parts
The braking system on a vehicle is
complex. Its many parts have to be
of top quality and work well together
if the vehicle is to have really good
braking. The vehicle was designed
and tested with top-quality brake
parts. When parts of the braking
system are replaced, be sure to get
new, approved replacement parts.
If this is not done, the brakes might
not work properly. For example,
installing disc brake pads that are
wrong for the vehicle, can change
the balance between the front and
rear brakes —for the worse. The
braking performance expected can
change in many other ways if the
wrong replacement brake parts are
installed.

Black plate (27,1)GMC Yukon/Yukon XL Owner Manual - 2012
Vehicle Care 10-27
Brake Fluid
The brake master cylinder reservoir
is filled with DOT 3 brake fluid. See
Engine Compartment Overview on
page 10‑6for the location of the
reservoir.
There are only two reasons why the
brake fluid level in the reservoir
might go down:
.The brake fluid level goes down
because of normal brake lining
wear. When new linings are
installed, the fluid level goes
back up.
.A fluid leak in the brake
hydraulic system can also cause
a low fluid level. Have the brake
hydraulic system fixed, since a
leak means that sooner or later
the brakes will not work well. Do not top off the brake fluid.
Adding fluid does not correct a leak.
If fluid is added when the linings are
worn, there will be too much fluid
when new brake linings are
installed. Add or remove brake fluid,
as necessary, only when work is
done on the brake hydraulic system.
{WARNING
If too much brake fluid is added, it
can spill on the engine and burn,
if the engine is hot enough. You
or others could be burned, and
the vehicle could be damaged.
Add brake fluid only when work is
done on the brake hydraulic
system. See
“Checking Brake
Fluid” in this section.
When the brake fluid falls to a low
level, the brake warning light comes
on. See Brake System Warning
Light on page 5‑23. Refer to the Maintenance Schedule
to determine when to check the
brake fluid. See
Maintenance
Schedule on page 11‑3.
Checking Brake Fluid
Check brake fluid by looking at the
brake fluid reservoir. See Engine
Compartment Overview on
page 10‑6.
The fluid level should be above
MIN. If it is not, have the brake
hydraulic system checked to see if
there is a leak.

Black plate (44,1)GMC Yukon/Yukon XL Owner Manual - 2012
10-44 Vehicle Care
FusesUsage
33 Daytime Running
Lamps 2 (If Equipped)
34 Sunroof
35 Key Ignition System,
Theft Deterrent
System
36 Windshield Wiper
37 SEO B2 Upfitter
Usage (Battery)
38 Electric Adjustable
Pedals
39 Climate Controls
(Battery)
40 Airbag System
(Ignition)
41 Amplifier
42 Audio System
43 Miscellaneous
(Ignition), Cruise
Control
44 Liftgate Release Fuses
Usage
45 Airbag System
(Battery)
46 Instrument Panel
Cluster
47 Not Used
48 Auxiliary Climate
Control (Ignition)
49 Center High-Mounted
Stoplamp (CHMSL)
50 Rear Defogger
51 Heated Mirrors
52 SEO B1 Upfitter
Usage (Battery)
53 Cigarette Lighter,
Auxiliary Power Outlet
54 Automatic Level
Control Compressor
Relay
55 Climate Controls
(Ignition) Fuses
Usage
56 Engine Control
Module, Secondary
Fuel Pump (Ignition)
J-Case Fuses Usage
57 Cooling Fan 1
58 Automatic Level
Control Compressor
59 Heavy Duty Antilock
Braking System
60 Cooling Fan 2
61 Antilock Brake
System 1
62 Starter
63 Stud 2 (Trailer
Brakes)
64 Left Bussed Electrical
Center 1
65 Electric Running
Boards

Black plate (53,1)GMC Yukon/Yukon XL Owner Manual - 2012
Vehicle Care 10-53
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.
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.

Black plate (61,1)GMC Yukon/Yukon XL Owner Manual - 2012
Vehicle Care 10-61
.Operating electronic devices or
being near facilities using radio
wave frequencies similar to the
TPMS could cause the TPMS
sensors to malfunction.
If the TPMS is not functioning
properly, it cannot detect or signal a
low tire condition. See your dealer
for service if the TPMS malfunction
light and DIC message comes on
and stays on.
TPMS Sensor Matching
Process
Each TPMS sensor has a unique
identification code. The identification
code needs to be matched to a new
tire/wheel position after rotating the
vehicle’s tires or replacing one or
more of the TPMS sensors. The
TPMS sensor matching process
should also be performed after
replacing a spare tire with a road
tire containing the TPMS sensor.
The malfunction light and the DIC
message should go off at the next
ignition cycle. The sensors are
matched to the tire/wheel positions, using a TPMS relearn tool, in the
following order: driver side front tire,
passenger side front tire, passenger
side rear tire, and driver side rear.
See your dealer for service or to
purchase a relearn tool.
There are two minutes to match
the first tire/wheel position, and
five minutes overall to match all
four tire/wheel positions. If it takes
longer, the matching process stops
and must be restarted.
The TPMS sensor matching process
is outlined below:
1. Set the parking brake.
2. Turn the ignition to ON/RUN with
the engine off.
3. Press
QandKon the Remote
Keyless Entry (RKE) transmitter
at the same time for
approximately five seconds. The
horn sounds twice to signal the
receiver is in relearn mode and
TIRE LEARNING ACTIVE
message displays on the DIC
screen. 4. Start with the driver side
front tire.
5. Place the relearn tool against the tire sidewall, near the valve
stem. Then press the button to
activate the TPMS sensor.
A horn chirp confirms that the
sensor identification code has
been matched to this tire and
wheel position.
6. Proceed to the passenger side front tire, and repeat the
procedure in Step 5.
7. Proceed to the passenger side rear tire, and repeat the
procedure in Step 5.
8. Proceed to the driver side rear tire, and repeat the procedure in
Step 5. The horn sounds two
times to indicate the sensor
identification code has been
matched to the driver side rear
tire, and the TPMS sensor
matching process is no longer
active. The TIRE LEARNING
ACTIVE message on the DIC
display screen goes off.

Black plate (64,1)GMC Yukon/Yukon XL Owner Manual - 2012
10-64 Vehicle Care
SeeTire Inspection on page 10‑62
and Tire Rotation on page 10‑62 for
additional information.
The rubber in tires ages over time.
This also applies to the spare tire,
if the vehicle has one, even if it is
never used. Multiple conditions
including temperatures, loading
conditions, and inflation pressure
maintenance affect how fast aging
takes place. Tires will typically
need to be replaced due to wear
before they may need to be
replaced due to age. Consult the
tire manufacturer for more
information on when tires
should be replaced.
Vehicle Storage
Tires age when stored normally
mounted on a parked vehicle. Park
a vehicle that will be stored for at
least a month in a cool, dry, clean
area away from direct sunlight to
slow aging. This area should be
free of grease, gasoline or other
substances that can deteriorate
rubber. Parking for an extended period can
cause flat spots on the tires that
may result in vibrations while
driving. When storing a vehicle for
at least a month, remove the tires or
raise the vehicle to reduce the
weight from the tires.
Buying New Tires
GM has developed and matched
specific tires for the vehicle. The
original equipment tires installed
were designed to meet General
Motors Tire Performance Criteria
Specification (TPC Spec) system
rating. When replacement tires are
needed, GM strongly recommends
buying tires with the same TPC
Spec rating.
GM's exclusive TPC Spec system
considers over a dozen critical
specifications that impact the
overall performance of the vehicle,
including brake system
performance, ride and handling,
traction control, and tire pressure
monitoring performance. GM's TPC
Spec number is molded onto the
tire's sidewall near the tire size.
If the tires have an all‐season tread
design, the TPC Spec number will
be followed by MS for mud and
snow. See
Tire Sidewall Labeling on
page 10‑50 for additional
information.
GM recommends replacing all the
tires at the same time. Uniform
tread depth on all tires will help to
maintain the performance of the
vehicle. Braking and handling
performance may be adversely
affected if all the tires are not
replaced at the same time. See Tire
Inspection on page 10‑62 andTire
Rotation on page 10‑62 for
information on proper tire rotation.

Black plate (89,1)GMC Yukon/Yukon XL Owner Manual - 2012
Vehicle Care 10-89
2. Get the vehicles close enoughso the jumper cables can reach,
but be sure the vehicles are not
touching each other. If they
are, it could cause a ground
connection you do not want. You
would not be able to start your
vehicle, and the bad grounding
could damage the electrical
systems.
To avoid the possibility of the
vehicles rolling, set the parking
brake firmly on both vehicles
involved in the jump start
procedure. Put the automatic
transmission in P (Park) or a
manual transmission in
N (Neutral) before setting the
parking brake. If the vehicle has
a four-wheel-drive transfer case
with a N (Neutral) position, be
sure the transfer case is in a
drive gear, not in N (Neutral). Notice:
If any accessories are left
on or plugged in during the jump
starting procedure, they could be
damaged. The repairs would
not be covered by the vehicle
warranty. Whenever possible,
turn off or unplug all accessories
on either vehicle when jump
starting the vehicle.
3. Turn off the ignition on both
vehicles. Unplug unnecessary
accessories plugged into the
cigarette lighter or the accessory
power outlets. Turn off the radio
and all the lamps that are not
needed. This avoids sparks and
helps save both batteries. And it
could save the radio! 4. Open the hood on the other
vehicle and locate the
positive (+) and negative (−)
terminal locations on that
vehicle.
Your vehicle has a remote
positive (+) jump starting
terminal and a remote
negative (−) jump starting
terminal. You should always use
these remote terminals instead
of the terminals on the battery.
If the vehicle has a remote
positive (+) terminal, it is located
under a red plastic cover at the
positive battery post. To uncover
the remote positive (+) terminal,
open the red plastic cover.

Black plate (98,1)GMC Yukon/Yukon XL Owner Manual - 2012
10-98 Vehicle Care
Four-Wheel Drive Vehicles with a
Two Speed Automatic
Transfer Case
Use the following procedure to dolly
tow a four-wheel drive vehicle from
the rear:
1. Attach the dolly to the towvehicle following the dolly
manufacturer's instructions.
2. Drive the rear wheels onto the dolly.
3. Firmly set the parking brake. See Parking Brake on
page 9‑45.
4. Put the transmission in P (Park).
5. Secure the vehicle to the dolly following the manufacturer's
instructions.
6. Use an adequate clamping device designed for towing to
ensure that the front wheels are
locked into the straight position.{WARNING
Shifting a four-wheel-drive
vehicle's transfer case into
N (Neutral) can cause the vehicle
to roll even if the transmission is
in P (Park). The driver or others
could be injured. Make sure the
parking brake is firmly set before
the transfer case is shifted to
N (Neutral).
7. Shift the transfer case to N (Neutral). See Four-Wheel
Drive (Two Speed Automatic
Transfer Case) on page 9‑37 or
Four-Wheel Drive (Single Speed
Automatic Transfer Case) on
page 9‑42.
8. Turn the ignition to LOCK/OFF.
After towing, see “Shifting Out of
N (Neutral)” underFour-Wheel Drive
(Two Speed Automatic Transfer
Case) on page 9‑37 orFour-Wheel
Drive (Single Speed Automatic
Transfer Case) on page 9‑42.
Appearance Care
Exterior Care
Washing the Vehicle
To preserve the vehicle's finish,
wash it often and out of direct
sunlight.
Notice: Do not use petroleum
based, acidic, or abrasive
cleaning agents as they can
damage the vehicle's paint, metal,
or plastic parts. If damage
occurs, it would not be covered
by the vehicle's warranty.
Approved cleaning products can
be obtained from your dealer.
Follow all manufacturer
directions regarding correct
product usage, necessary safety
precautions, and appropriate
disposal of any vehicle care
product.

Black plate (9,1)GMC Yukon/Yukon XL Owner Manual - 2012
Service and Maintenance 11-9
.To avoid break‐down or failure to
start the vehicle, maintain a
battery with full cranking power.
.Trained dealer technicians have
the diagnostic equipment to test
the battery and ensure that the
connections and cables are
corrosion‐free.
Belts
.Belts may need replacing if they
squeak or show signs of
cracking or splitting.
.Trained dealer technicians can
inspect the belts and
recommend replacement when
necessary.
Brakes
Brakes stop the vehicle and are
crucial to safe driving.
.Signs of brake wear may include
chirping, grinding, or squealing
noises, or difficulty stopping.
.Trained dealer technicians have
access to tools and equipment
to inspect the brakes and
recommend quality parts
engineered for the vehicle.
Fluids
Proper fluid levels and approved
fluids protect the vehicle’s systems
and components. See
Recommended Fluids and
Lubricants on page 11‑11 for GM
approved fluids.
.Engine oil and windshield
washer fluid levels should be
checked at every fuel fill.
.Instrument cluster lights may
come on to indicate that fluids
may be low and need to be
filled.
Hoses
Hoses transport fluids and should
be regularly inspected to ensure
that there are no cracks or leaks.
With a multi‐point inspection, your
dealer can inspect the hoses and
advise if replacement is needed. Lamps
Properly working headlamps,
taillamps, and brake lamps are
important to see and be seen on
the road.
.Signs that the headlamps need
attention include dimming, failure
to light, cracking, or damage.
The brake lamps need to be
checked periodically to ensure
that they light when braking.
.With a multi‐point inspection,
your dealer can check the lamps
and note any concerns.
Shocks and Struts
Shocks and struts help aid in control
for a smoother ride.
.Signs of wear may include
steering wheel vibration, bounce/
sway while braking, longer
stopping distance, or uneven
tire wear.

Black plate (1,1)GMC Yukon/Yukon XL Owner Manual - 2012
INDEX i-1
A
Accessories andModifications . . . . . . . . . . . . . . . . . 10-3
Accessory Power . . . . . . . . . . . . . . 9-27
Active Fuel Management
®. . . . . 9-29
Add-On Electrical Equipment . . . . . . . . . . . . . . . . . . . 9-86
Adding a Snow Plow or Similar Equipment . . . . . . . . . . . . 9-86
Additional Information, OnStar
®. . . . . . . . . . . . . . . . . . . . . . 14-5
Adjustable Throttle and Brake Pedal . . . . . . . . . . . . . . . . . . 9-22
Adjustments Lumbar, Front Seats . . . . . . . . . . . 3-4
Air Cleaner/Filter, Engine . . . . . 10-15
Air Vents . . . . . . . . . . . . . . . . . . . . . . 8-13
Airbag
Adding Equipment to theVehicle . . . . . . . . . . . . . . . . . . . . . . 3-42 Airbag System
Check . . . . . . . . . . . . . . . . . . . . . . . . 3-44
How Does an Airbag
Restrain? . . . . . . . . . . . . . . . . . . . 3-36
Passenger Sensing System . . . . . . . . . . . . . . . . . . . . . . 3-38
What Makes an Airbag
Inflate? . . . . . . . . . . . . . . . . . . . . . . 3-35
What Will You See after an Airbag Inflates? . . . . . . . . . . . . . 3-36
When Should an Airbag
Inflate? . . . . . . . . . . . . . . . . . . . . . . 3-34
Where Are the Airbags? . . . . . . 3-32
Airbags Passenger Status Indicator . . . 5-19
Readiness Light . . . . . . . . . . . . . . 5-18
Servicing Airbag-EquippedVehicles . . . . . . . . . . . . . . . . . . . . . 3-42
System Check . . . . . . . . . . . . . . . . 3-30
Alarm System Anti-theft . . . . . . . . . . . . . . . . . . . . . . 2-14
AM-FM Radio . . . . . . . . . . . . . . . . . . . 7-7 Antenna
Rear Side Window . . . . . . . . . . . . 7-13
Satellite Radio . . . . . . . . . . . . . . . . 7-14
Anti-theft Alarm System . . . . . . . . . . . . . . . . 2-14
Alarm System Messages . . . . . 5-44
Antilock Brake
System (ABS) . . . . . . . . . . . . . . . . 9-44
Warning Light . . . . . . . . . . . . . . . . . 5-24
Appearance Care Exterior . . . . . . . . . . . . . . . . . . . . . 10-98
Interior . . . . . . . . . . . . . . . . . . . . . 10-101
Armrest Storage . . . . . . . . . . . . . . . . 4-1
Assistance Program, Roadside . . . . . . . . . . . . . . . . . . . . . 13-5
Audio Players . . . . . . . . . . . . . . . . . 7-14
CD . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-14
CD/DVD . . . . . . . . . . . . . . . . . . . . . . 7-19
Audio System Radio Reception . . . . . . . . . . . . . . 7-12
Rear Seat (RSA) . . . . . . . . . . . . . 7-45
Theft-Deterrent Feature . . . . . . . . 7-2