2010 GMC SIERRA ECU

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
fluid, 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.
Heavy-DutyTrailer 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*
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Turn the pressure cap slowly counterclockwise
about one full turn. If you hear a hiss, wait for that
to stop. A hiss means there is still some
pressure left.
2. Keep turning the pressure cap slowly, and remove it.
3. Fill the coolant surge tank with the proper mixtureto the FULL COLD mark.
4. With the coolant surge tank pressure cap off, start the engine and let it run until the engine coolant
temperature gage indicates approximately
195°F (90°C). By this time, the coolant level inside the coolant
surge tank may be lower. If the level is lower, add
more of the proper mixture to the coolant surge
tank until the level reaches the FULL COLD mark.
5. Replace the pressure cap. Be sure the pressure cap is hand-tight and fully seated.
6. Verify coolant level after engine is shut off and the coolant is cold. If necessary, repeat coolant fill
procedure Steps 1 through 6.
Notice: If the pressure cap is not tightly installed,
coolant loss and possible engine damage may
occur. Be sure the cap is properly and tightly
secured.
Engine Overheating
If the vehicle has the DURAMAX®Diesel engine, see
the DURAMAX®Diesel manual for more information.
The vehicle has several indicators to warn of engine
overheating.
You will find a coolant temperature gage on the
vehicle's instrument panel. See Engine Coolant
Temperature Gage on page 4‑41.
In addition, you will find ENGINE OVERHEATED STOP
ENGINE, ENGINE OVERHEATED IDLE ENGINE, and
ENGINE POWER IS REDUCED messages in the Driver
Information Center (DIC) on the instrument panel.
See DIC Warnings and Messages on page 4‑65.
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4. Turn the bulb socket counterclockwise to remove itfrom the headlamp assembly and pull it
straight out.
5. Unplug the electrical connector from the old bulb by releasing the clips on the bulb socket.
6. Replace it with a new bulb socket.
7. Plug in the electrical connector to the new bulb socket.
8. Reinstall the new bulb socket into the headlamp assembly and turn it clockwise to secure.
9. Close the hood.
Center High-Mounted Stoplamp
(CHMSL) and Cargo Lamp
To replace one of these bulbs:
1. Remove the screws and lift off the lamp assembly.
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Make certain that all wheel nuts are properly
tightened. See“Wheel Nut Torque” under
Capacities and Specifications
on page 6‑126.
{WARNING:
Rust or dirt on a wheel, or on the parts to
which it is fastened, can make wheel nuts
become loose after time. The wheel could
come off and cause an accident. When you
change a wheel, remove any rust or dirt from
places where the wheel attaches to the
vehicle. In an emergency, you can use a
cloth or a paper towel to do this; but be sure
to use a scraper or wire brush later,
if needed, to get all the rust or dirt off.
See Changing a Flat Tire
on page 6‑90.
If your vehicle has a Tire Pressure Monitor
System (TPMS), reset the TPMS sensors after
rotating the tires. See Tire Pressure Monitor
Operation
on page 6‑76. Make sure the spare tire, if your vehicle has one,
is stored securely. Push, pull, and then try to
rotate or turn the tire. If it moves, tighten the
cable. See
Storing a Flat or Spare Tire and Tools
on page 6‑106.
When It Is Time for New Tires
Various factors, such as maintenance, temperatures,
driving speeds, vehicle loading, and road conditions,
influence when you need new tires.
One way to tell when it is
time for new tires is to
check the treadwear
indicators, which appear
when your tires have only
1/16 inch (1.6 mm) or less
of tread remaining. Some
commercial truck tires
may not have treadwear
indicators.
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Tire Chains
{WARNING:
If your vehicle has dual wheels or P265/65R18,
P275/55R20 or LT265/70R17 size tires, do not
use tire chains. They can damage your vehicle
because there is not enough clearance. Tire
chains used on a vehicle without the proper
amount of clearance can cause damage to the
brakes, suspension, or other vehicle parts. The
area damaged by the tire chains could cause you
to lose control of your vehicle and you or others
may be injured in a crash.
Use another type of traction device only if its
manufacturer recommends it for use on your
vehicle and tire size combination and road
conditions. Follow that manufacturer's
instructions. To help avoid damage to your
vehicle, drive slowly, readjust, or remove the
device if it is contacting your vehicle, and do not
spin your vehicle's wheels.
If you do find traction devices that will fit, install
them on the rear tires.Notice:
If your vehicle does not have dual
wheels and has a tire size other than P265/65R18,
P275/55R20 or LT265/70R17, use tire chains only
where legal and only when you must. Use chains
that are the proper size for your tires. Install them
on the tires of the rear axle. Do not use chains on
the tires of the front axle. Tighten them as tightly as
possible with the ends securely fastened. Drive
slowly and follow the chain manufacturer's
instructions. If you can hear the chains contacting
your vehicle, stop and retighten them. If the contact
continues, slow down until it stops. Driving too fast
or spinning the wheels with chains on will damage
your vehicle.
If a Tire Goes Flat
It is unusual for a tire to blowout while you are driving,
especially if you maintain your vehicle's tires properly.
If air goes out of a tire, it is much more likely to leak out
slowly. But if you should ever have a blowout, here are
a few tips about what to expect and what to do:
If a front tire fails, the flat tire creates a drag that pulls
the vehicle toward that side. Take your foot off the
accelerator pedal and grip the steering wheel firmly.
Steer to maintain lane position, and then gently brake to
a stop well out of the traffic lane.
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Make sure that the jack head is positioned so that
the rear axle is resting securely between the
grooves that are on the jack head.
{WARNING:
Getting under a vehicle when it is jacked up is
dangerous. If the vehicle slips off the jack, you
could be badly injured or killed. Never get under a
vehicle when it is supported only by a jack.
{WARNING:
Raising your vehicle with the jack improperly
positioned can damage the vehicle and even
make the vehicle fall. To help avoid personal
injury and vehicle damage, be sure to fit the
jack lift head into the proper location before
raising the vehicle.
6. Turn the wheel wrench clockwise to raise the vehicle. Raise the vehicle far enough off the
ground so there is enough room for the spare tire
to fit under the wheel well.
7. Remove all the wheelnuts and take off the
flat tire.
{WARNING:
Rust or dirt on a wheel, or on the parts to which it
is fastened, can make wheel nuts become loose
after time. The wheel could come off and cause
an accident. When changing a wheel, remove any
rust or dirt from places where the wheel attaches
to the vehicle. In an emergency, use a cloth or a
paper towel to do this; but be sure to use a
scraper or wire brush later, if needed, to get all the
rust or dirt off. See Changing a Flat Tire
on
page 6‑90
.
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5. If the spare does not lower, turn the wrenchcounterclockwise until approximately 6 inches
(15 cm) of cable is exposed.
6. Stand the wheel blocks on their shortest ends, with the backs facing each other.
7. Place the bottom edgeof the jack (A) on the
wheel blocks (B),
separating them so that
the jack is balanced
securely.
8. Attach the jack handle, extension, and wheelwrench to the jack and place it (with the wheel
blocks) under the vehicle toward the front of the
rear bumper.
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5. Raise the tire part way upward. Make sure theretainer is seated in the wheel opening.
6. Raise the tire fully against the underside of the vehicle by turning the wheel wrench clockwise until
you hear two clicks or feel it skip twice. You cannot
overtighten the cable.
7. Make sure the tire is stored securely. Push,pull (A), and then try to turn (B) the tire. If the tire
moves, use the wheel wrench to tighten the cable.
8. Reinstall the spare tire lock, if the vehicle has one. To store the jack and jack tools:
A. Wing Nut Retaining
Wheel Blocks
B. Wheel Blocks
C. Wing Nut Retaining Tool Kit
D. Wheel Wrench and Extensions E. Tool Bag
F. Jack Mounting Bracket
G. Jack H. Bolt Retaining Wheel Blocks
1. Put the tools (D) in the tool bag (E) and place them in the retaining bracket (C).
2. Tighten down the wing nut (C).
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