2009 GMC SIERRA brake light

Maintenance When Trailer Towing
The vehicle needs service more often when pulling a
trailer. See this manual’s Maintenance Schedule or Index
for more information. Things that are especially important
in trailer operation are automatic transmission uid,
engine oil, axle lubricant, belts, cooling system and brake
system. It is a good idea to inspect these before and
during the trip.
Check periodically to see that all hitch nuts and bolts
are tight.
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/retailer.
If towing a light-duty trailer with a standard four-way
round pin connector, an adapter is available from your
dealer/retailer.
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Heavy-Duty Trailer Wiring Harness
Package
For vehicles equipped with heavy duty trailering, the
harness is connected to a bracket on the hitch platform.
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/retailer or a qualied 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/retailer or authorized
service center install the required fuse.
If charging a remote (non-vehicle) battery, press the
tow/haul mode button 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, turn on the headlamps as a second way to boost
the vehicle system and charge the battery.
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Camper/Fifth-Wheel Trailer Wiring Package
The seven-wire camper harness is located under the
front edge of the pickup box on the drivers 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 BrakeIf 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, an eight-wire harness
with a seven-pin connector is located at the rear of
the vehicle and is tied to the vehicle’s frame.
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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
It should be installed by your dealer/retailer or a
qualied service center.
If the vehicle is equipped with an ITBC, the blunt cuts
exist, but are not connected further in the harness.
If an aftermarket trailer brake controller is installed,
the ITBC must be disconnected. Do not power
both ITBC and aftermarket controllers to control
the trailer brakes at the same time.
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 drivers side of
the vehicle, next to the underhood electrical center.Be sure to follow the proper installation instructions
that are included with any electrical equipment that
is installed.
Notice:Leaving electrical equipment on for
extended periods will drain the battery. Always turn
off electrical equipment when not in use and do
not use equipment that exceeds the maximum
amperage rating for the auxiliary battery provision.
Trailer Recommendations
Subtract the hitch loads from the Cargo Weight Rating
(CWR). CWR is the maximum weight of the load the
vehicle can carry. It does not include the weight of the
people inside, but you can gure about 150 lbs. (68 kg)
for each passenger. The total cargo load must not be
more than the vehicles CWR.
Weigh the vehicle with the trailer attached, so
the GVWR or GAWR are not exceeded. If using a
weight-distributing hitch, weigh the vehicle without
the spring bars in place.
The best performance is obtained by correctly spreading
out the weight of the load and choosing the correct
hitch and trailer brakes.
For more information seeTowing a Trailer on page 4-51.
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Brake Wear
This vehicle has front disc brakes and could have rear
drum brakes or rear 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 rmly.
{CAUTION:
The brake wear warning sound means that soon
the brakes will not work well. That could lead to an
accident. 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 rst 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 specications in
Capacities and Specifications on page 5-129.
If the vehicle has rear drum brakes, they do not have
wear indicators, but if a rear brake rubbing noise is heard,
have the rear brake linings inspected immediately.
Rear brake drums should be removed and inspected
each time the tires are removed for rotation or changing.
Drum brakes have an inspection hole to inspect lining
wear during scheduled maintenance. When the front
brake pads are replaced, have the rear brakes
inspected, too.
Brake linings should always be replaced as complete
axle sets.
Brake Pedal Travel
See your dealer/retailer 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 brake stop, the brakes adjust for wear.
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Notice:If the other vehicle’s system is not a 12-volt
system with a negative ground, both vehicles can
be damaged. Only use vehicles with 12-volt systems
with negative grounds to jump start your vehicle.
2. If you have a vehicle with a diesel engine with two
batteries, you should know before you begin that,
especially in cold weather, you may not be able
to get enough power from a single battery in another
vehicle to start your diesel engine. If your vehicle
has more than one battery, use the battery that
is closer to the starter -- this will reduce electrical
resistance. This is located on the passenger side, in
the rear of the engine compartment.
3. Get the vehicles close enough so the jumper cables
can reach, but be sure the vehicles are not touching
each other. If they are, it could cause an unwanted
ground connection. 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 rmly on both vehicles involved in the
jump start procedure. Put the automatic transmission
in P (Park) or a manual transmission in Neutral
before setting the parking brake. If you have a
four-wheel-drive vehicle, be sure the transfer
case is in a drive gear, not in Neutral.Notice:If you leave the radio or other accessories
on during the jump starting procedure, they could be
damaged. The repairs would not be covered by the
warranty. Always turn off the radio and other
accessories when jump starting the vehicle.
4. 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 will avoid sparks and help save both batteries.
And it could save the radio!
5. Open the hood on the other vehicle and locate the
positive (+) and negative (−) terminal locations on
that vehicle.
The positive (+) terminal, is located under a red
plastic cover at the positive battery post. To uncover
the positive (+) terminal, open the red plastic cover.
5-45

(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) Service Description
:The service description
indicates the load range and speed rating of a
tire. The load index represents the load carry
capacity a tire is certied to carry. The load index
can range from 1 to 279. The speed rating is
the maximum speed a tire is certied to carry a
load. Speed ratings range from A to Z.
Tire Terminology and Denitions
Air Pressure:The amount of air inside the
tire pressing outward on each square inch of the
tire. Air pressure is expressed in pounds per
square inch (psi) or kilopascal (kPa).
Accessory Weight
:This means 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.
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.
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Different Size Tires and Wheels
If you add wheels or tires that are a different size than
your original equipment wheels and tires, this could
affect the way your vehicle performs, including its
braking, ride and handling characteristics, stability, and
resistance to rollover. Additionally, if your vehicle
has electronic systems such as anti-lock brakes, rollover
airbags, traction control, and electronic stability control,
the performance of these systems can be affected.
{CAUTION:
If you add different sized wheels, your vehicle may
not provide an acceptable level of performance
and safety if tires not recommended for those
wheels are selected. You may increase the
chance that you will crash and suffer serious
injury. Only use GM specic wheel and tire
systems developed for your vehicle, and have
them properly installed by a GM certied
technician.
SeeBuying New Tires on page 5-84andAccessories
and Modifications on page 5-4for additional information.
Uniform Tire Quality Grading
Quality grades can be found where applicable on
the tire sidewall between tread shoulder and
maximum section width. For example:
Treadwear 200 Traction AA
Temperature A
The following information relates to the system
developed by the United States National
Highway Traffic Safety Administration (NHTSA),
which grades tires by treadwear, traction, and
temperature performance. This applies only to
vehicles sold in the United States. The grades are
molded on the sidewalls of most passenger car
tires. The Uniform Tire Quality Grading (UTQG)
system does not apply to deep tread, winter-type
snow tires, space-saver, or temporary use spare
tires, tires with nominal rim diameters of
10 to 12 inches (25 to 30 cm), or to some
limited-production tires.
While the tires available on General Motors
passenger cars and light trucks may vary with
respect to these grades, they must also conform
to federal safety requirements and additional
General Motors Tire Performance Criteria (TPC)
standards.
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