2010 GMC SIERRA light

WARNING: (Continued)
If the vehicle is stuck in the snow:
.Clear away snow from around the base of
your vehicle, especially any that is blocking
the exhaust pipe.
.Check again from time to time to be sure
snow does not collect there.
.Open a window about 5 cm (two inches) on
the side of the vehicle that is away from the
wind to bring in fresh air.
.Fully open the air outlets on or under the
instrument panel.
.Adjust the Climate Control system to a setting
that circulates the air inside the vehicle and
set the fan speed to the highest setting.
See Climate Control System in the Index.
For more information about carbon monoxide, see
Engine Exhaust on page 3‑54.
Snow can trap exhaust gases under your vehicle.
This can cause deadly CO (carbon monoxide) gas
to get inside. CO could overcome you and kill you. (Continued)
WARNING: (Continued)
You cannot see it or smell it, so you might not
know it is in your vehicle. Clear away snow from
around the base of your vehicle, especially any
that is blocking the exhaust.
Run the engine for short periods only as needed to
keep warm, but be careful.
To save fuel, run the engine for only short periods as
needed to warm the vehicle and then shut the engine
off and close the window most of the way to save heat.
Repeat this until help arrives but only when you feel
really uncomfortable from the cold. Moving about to
keep warm also helps.
If it takes some time for help to arrive, now and then
when you run the engine, push the accelerator pedal
slightly so the engine runs faster than the idle speed.
This keeps the battery charged to restart the vehicle
and to signal for help with the headlamps. Do this as
little as possible to save fuel.
5-27

If Your Vehicle is Stuck in Sand,
Mud, Ice, or Snow
Slowly and cautiously spin the wheels to free the
vehicle when stuck in sand, mud, ice, or snow. See
Rocking Your Vehicle to Get It Out on page 5‑28.
If the vehicle has a traction system, it can often help
to free a stuck vehicle. Refer to the vehicle's traction
system in the Index. If stuck too severely for the traction
system to free the vehicle, turn the traction system off
and use the rocking method.
{WARNING:
If the vehicle's tires spin at high speed, they can
explode, and you or others could be injured.
The vehicle can overheat, causing an engine
compartment fire or other damage. Spin the
wheels as little as possible and avoid going above
55 km/h (35 mph) as shown on the speedometer.
For information about using tire chains on the vehicle,
see Tire Chains on page 6‑89.
Rocking Your Vehicle to Get It Out
Turn the steering wheel left and right to clear the
area around the front wheels. For four-wheel-drive
vehicles, shift into Four‐Wheel High. For vehicles with
StabiliTrak
®, turn the traction control part of the system
off. Shift back and forth between R (Reverse) and a
forward gear, spinning the wheels as little as possible.
To prevent transmission wear, wait until the wheels stop
spinning before shifting gears. Release the accelerator
pedal while shifting, and press lightly on the accelerator
pedal when the transmission is in gear. Slowly spinning
the wheels in the forward and reverse directions causes
a rocking motion that could free the vehicle. If that does
not get the vehicle out after a few tries, it might need
to be towed out. Recovery hooks can be used, if the
vehicle has them. If the vehicle does need to be towed
out, see Towing Your Vehicle on page 5‑43.
5-28

Weight‐Distributing Hitch Adjustment
A :Body to Ground Distance
B : Front of Vehicle
When using a weight-distributing hitch, the spring
bars should be adjusted so the distance (A) is the
same after coupling the trailer to the tow vehicle and
adjusting the hitch.
Fifth Wheel and Gooseneck Trailering
Fifth wheel and gooseneck trailers can be used
with many pickup models. These trailers place a
larger percentage of the weight (kingpin weight) on the
tow vehicle than conventional trailers. Make sure this
weight does not cause the vehicle to exceed GAWR
or GVWR.
Fifth wheel or gooseneck kingpin weight should be
15 to 25 percent of the trailer weight up to the maximum
amount specified in the trailering chart for the vehicle.
See “Weight of the Trailer” in this section for more
information.
The hitch should be located in the pickup bed so that
its centerline is over or slightly in front of the rear axle.
Take care that it is not so far forward that it will contact
the back of the cab in sharp turns. This is especially
important for short box pickups. Trailer pin box
extensions and sliding fifth wheel hitch assemblies can
help this condition. There should be at least six inches
of clearance between the top of the pickup box and the
bottom of the trailer shelf that extends over the box.
Make sure the hitch is attached to the tow vehicle frame
rails. Do not use the pickup box for support.
5-62

Safety Chains
Always attach chains between the vehicle and the
trailer. Cross the safety chains under the tongue of the
trailer to help prevent the tongue from contacting the
road if it becomes separated from the hitch. Instructions
about safety chains may be provided by the hitch
manufacturer or by the trailer manufacturer. If the trailer
being towed weighs up to 5,000 lbs (2 271 kg) with a
factory-installed step bumper, safety chains may be
attached to the attaching points on the bumper,
otherwise, safety chains should be attached to holes on
the trailer hitch platform. Always leave just enough
slack so the combination can turn. Never allow safety
chains to drag on the ground.
Tow/Haul Mode
Pressing this button
at the end of the shift
lever turns on and off
the tow/haul mode.
This indicator light on
the instrument panel
cluster comes on when
the tow/haul mode is on.
Tow/Haul is a feature that assists when pulling a heavy
trailer or a large or heavy load. See Tow/Haul Mode
on
page 3‑34for more information.
Tow/Haul is designed to be most effective when
the vehicle and trailer combined weight is at least
75 percent of the vehicle's Gross Combined Weight
Rating (GCWR). See “Weight of the Trailer” later in the
section. Tow/Haul is most useful under the following
driving conditions:
.When pulling a heavy trailer or a large or heavy
load through rolling terrain.
.When pulling a heavy trailer or a large or heavy
load in stop and go traffic.
.When pulling a heavy trailer or a large or heavy
load in busy parking lots where improved low
speed control of the vehicle is desired.
Operating the vehicle in Tow/Haul when lightly loaded
or with no trailer at all will not cause damage. However,
there is no benefit to the selection of Tow/Haul when the
5-63

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*
5-74

*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 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/retailer 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 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 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 Brake
5-75

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, 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.
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
qualified 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.
5-76

The 8th digit of the Vehicle Identification Number (VIN)
shows the code letter or number that identifies the
vehicle's engine. The VIN is at the top left of the
instrument panel. SeeVehicle Identification Number
(VIN) on page 6‑117.
If the vehicle has the 5.3L V8 engine (VIN Code 0),
the 5.3L V8 engine (VIN Code 3), the 6.0L V8 engine
(VIN Code J), or the 6.2L V8 engine (VIN Code 2),
you can use either unleaded gasoline or ethanol fuel
containing up to 85% ethanol (E85). See Fuel E85
(85% Ethanol)
on page 6‑9. In all other gasoline
engines, use only unleaded gasoline. See Gasoline
Octane on page 6‑7.
Gasoline Octane
For all vehicles except those with the 6.2L V8 engine
(VIN Code 2), use regular unleaded gasoline with a
posted octane rating of 87 or higher. If the octane rating
is less than 87, an audible knocking noise, commonly
referred to as spark knock, might be heard when
driving. If this occurs, use a gasoline rated at 87 octane
or higher as soon as possible. If heavy knocking is
heard when using gasoline rated at 87 octane or higher,
the engine needs service. If the vehicle has the 6.2L V8 engine (VIN Code 2), use
premium unleaded gasoline with a posted octane rating
of 91 or higher. You can also use regular unleaded
gasoline rated at 87 octane or higher, but the vehicle's
acceleration could be slightly reduced, and a slight
audible knocking noise, commonly referred to as spark
knock, might be heard. If the octane is less than 87, you
might notice a heavy knocking noise when you drive.
If this occurs, use a gasoline rated at 87 octane or
higher as soon as possible. Otherwise, you could
damage the engine. If heavy knocking is heard when
using gasoline rated at 87 octane or higher, the engine
needs service.
Gasoline Specifications
At a minimum, gasoline should meet ASTM
specification D 4814 in the United States or
CAN/CGSB‐3.5 or 3.511 in Canada. Some
gasolines contain an octane-enhancing additive
called methylcyclopentadienyl manganese tricarbonyl
(MMT). We recommend against the use of gasolines
containing MMT. See
Additives
on page 6‑8for
additional information.
6-7