2009 GMC SIERRA light

{CAUTION:
Snow can trap engine exhaust under the vehicle.
This may cause exhaust gases to get inside.
Engine exhaust contains carbon monoxide (CO)
which cannot be seen or smelled. It can cause
unconsciousness and even death.
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 two inches (5 cm) 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.
CAUTION: (Continued)
CAUTION: (Continued)
For more information about carbon monoxide, see
Engine Exhaust on page 2-55.
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.
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.
4-29

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.
SeeRocking Your Vehicle to Get It Out on page 4-30.
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.
{CAUTION:
If you let your 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 re or other damage.
Spin the wheels as little as possible and avoid
going above 35 mph (55 km/h) as shown on the
speedometer.
For information about using tire chains on the vehicle,
seeTire Chains on page 5-90.
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, seeTowing
Your Vehicle on page 4-45.
4-30

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 specied 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
fth 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.
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. If the trailer being towed
weighs up to the vehicle’s trailer rating limit, safety chains
may be attached to the attaching point on the hitch
platform. Always leave just enough slack so the rig can
turn. Never allow safety chains to drag on the ground.
4-68

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. SeeTow/Haul Mode
on page 2-34for 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 benet to the selection of Tow/Haul when
the vehicle is unloaded. Such a selection when unloaded
may result in unpleasant engine and transmission
driving characteristics and reduced fuel economy.
Tow/Haul is recommended only when pulling a
heavy trailer or a large or heavy load.
4-69

Driving On Grades
Reduce speed and shift to a lower gearbeforestarting
down a long or steep downgrade. If the transmission is
not shifted down, the brakes might have to be used so
much that they would get hot and no longer work well.
Vehicles can tow in D (Drive). Shift the transmission to
a lower gear if the transmission shifts too often under
heavy loads and/or hilly conditions.
The tow/haul mode may be used if the transmission
shifts too often. SeeTow/Haul Mode Light on page 3-51.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a lower
temperature than at normal altitudes. If the engine is
turned off immediately after towing at high altitude on
steep uphill grades, the vehicle may show signs similar to
engine overheating. To avoid this, let the engine run while
parked, preferably on level ground, with the automatic
transmission in P (Park) for a few minutes before turning
the engine off. If the overheat warning comes on, see
Engine Overheating on page 5-34.
Parking on Hills
{CAUTION:
Parking the vehicle on a hill with the trailer
attached can be dangerous. If something goes
wrong, the rig could start to move. People can
be injured, and both the vehicle and the trailer
can be damaged. When possible, always park
the rig on a at surface.
If parking the rig on a hill:
1. Press the brake pedal, but do not shift into P (Park)
yet. Turn the wheels into the curb if facing downhill
or into traffic if facing uphill.
2. Have someone place chocks under the trailer
wheels.
3. When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
4-79

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.
4-81

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.
4-82

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.
4-83