brake GMC SIERRA 1500 2012 Repair Manual
[x] Cancel search | Manufacturer: GMC, Model Year: 2012, Model line: SIERRA 1500, Model: GMC SIERRA 1500 2012Pages: 556, PDF Size: 7.88 MB
Page 335 of 556
Black plate (59,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-59
I(On/Off):Press to turn the
system on or off. The indicator light
is on when cruise control is on and
turns off when cruise control is off.
+ RES (Resume/Accelerate):
Press briefly to resume to a
previously set speed, or press and
hold to accelerate.
SET −(Set/Coast): Press to set
the speed and activate cruise
control or make the vehicle
decelerate.
[(Cancel): Press to disengage
cruise control without erasing the
set speed from memory.
Setting Cruise Control
If the cruise button is on when not in
use, it could get bumped and go into
cruise when not desired. Keep the
cruise control switch off when cruise
is not being used.
The cruise control light on the
instrument panel cluster will come
on after the cruise control has been
set to the desired speed.
1. Press
I.
2. Get up to the desired speed.
3. Press the SET− button located
on the steering wheel and
release it.
4. Take your foot off the accelerator. Resuming a Set Speed
If the cruise control is set at a
desired speed and then the brakes
are applied, the cruise control is
disengaged without erasing the set
speed from memory.
Once the vehicle speed reaches
about 40 km/h (25 mph) or more,
press the +RES button on the
steering wheel. The vehicle returns
to the previous set speed and stays
there.
Increasing Speed While Using
Cruise Control
If the cruise control system is
already activated,
.Press and hold the +RES button
on the steering wheel until the
desired speed is reached, then
release it.
.To increase vehicle speed in
small amounts, press the
+RES button. Each time this is
done, the vehicle goes about
1.6 km/h (1 mph) faster.
Page 336 of 556
Black plate (60,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-60 Driving and Operating
Reducing Speed While Using
Cruise Control
If the cruise control system is
already activated,
.Press and hold the SET–button
on the steering wheel until the
desired lower speed is reached,
then release it.
.To slow down in small amounts,
press the SET– button on the
steering wheel briefly. Each time
this is done, the vehicle goes
about 1.6 km/h (1 mph) slower.
Passing Another Vehicle While
Using Cruise Control
Use the accelerator pedal to
increase the vehicle speed. When
you take your foot off the pedal,
the vehicle will slow down to the
previous set cruise speed.
Using Cruise Control on Hills
How well the cruise control works
on hills depends on the vehicle
speed, the load, and the steepness
of the hills. When going up steep hills, pressing the accelerator pedal
may be necessary to maintain
vehicle speed.
While going downhill:
.Vehicles with a four speed
automatic transmission may
need to have the brakes applied
or the transmission shifted
to a lower gear to keep the
speed down.
.Vehicles with a six speed
automatic transmission have a
Cruise Grade Braking feature
that may automatically shift to a
lower gear to keep the speed
down. It may be necessary to
apply the brake or manually
shift the transmission to a lower
gear. The vehicle may shift to a
higher gear when grade braking
assistance is no longer required.
Cruise Grade Braking is not
available while in Range
Selection Mode. This feature is
active when the exhaust brake
is enabled (if equipped). See
"Range Selection Mode" under
Manual Mode on page 9‑38.
When the brakes are manually
applied the cruise control is
disengaged.
Ending Cruise Control
There are three ways to end cruise
control:.To disengage cruise control;
step lightly on the brake pedal.
.Press[on the steering wheel.
.To turn off the cruise control,
press
Ion the steering wheel.
Erasing Speed Memory
The cruise control set speed
is erased from memory by
pressing
Ior if the ignition is
turned off.
Page 338 of 556
Black plate (62,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-62 Driving and Operating
URPA defaults to the on setting
each time the vehicle is started.
Notice:If you use URPA while the
tailgate is lowered, it may not
detect an object behind your
vehicle, and you might back into
the object and damage your
vehicle. Always verify the tailgate
is closed when using URPA or
turn off URPA when driving with
the tailgate lowered.
When the System Does Not
Seem to Work Properly
The following messages may be
displayed on the DIC:
SERVICE PARK ASSIST: If this
message occurs, take the vehicle to
your dealer to repair the system. PARK ASST BLOCKED SEE
OWNERS MANUAL:
This
message can occur under the
following conditions:
.The ultrasonic sensors are not
clean. Keep the vehicle's rear
bumper free of mud, dirt, snow,
ice, and slush. For cleaning
instructions, see Exterior Care
on page 10‑98.
.The park assist sensors are
covered by frost or ice. Frost or
ice can form around and behind
the sensors and may not always
be seen; this can occur after
washing the vehicle in cold
weather. The message may not
clear until the frost or ice has
melted.
.A trailer was attached to the
vehicle, or an object was
hanging out of the tailgate during
the last drive cycle. Once the
object is removed and the
tailgate is raised, URPA will
return to normal operation.
.A tow bar is attached to the
vehicle.
.The bumper is damaged. Take
the vehicle to your dealer to
repair the system.
.Other conditions, such as
vibrations from a jackhammer or
the compression of air brakes on
a very large truck, are affecting
system performance.
Rear Vision
Camera (RVC)
If available, the Rear Vision Camera
(RVC) system displays part of the
scene behind the vehicle.
{WARNING
The RVC system does not display
pedestrians, bicyclists, animals,
or any other object located
outside the camera's field of view,
below the bumper, or under the
vehicle. Do not back the vehicle
(Continued)
Page 351 of 556
Black plate (75,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-75
Driving with a Trailer
{WARNING
When towing a trailer, exhaust
gases may collect at the rear of
the vehicle and enter if the
liftgate, trunk/hatch, or rear-most
window is open.
Engine exhaust contains Carbon
Monoxide (CO) which cannot be
seen or smelled. It can cause
unconsciousness and even death.
To maximize safety when towing
a trailer:
.Have the exhaust system
inspected for leaks and make
necessary repairs before
starting a trip.
.Never drive with the liftgate,
trunk/hatch, or rear-most
window open.(Continued)
WARNING (Continued)
.Fully open the air outlets on
or under the instrument
panel.
.Adjust the Climate Control
system to a setting that
brings in only outside air 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 9‑33.
Towing a trailer requires a certain
amount of experience. The
combination you are driving is
longer and not as responsive as the
vehicle itself. Get acquainted with
the handling and braking of the rig
before setting out for the open road.
Before starting, check all trailer
hitch parts and attachments,
safety chains, electrical connectors, lamps, tires, and mirrors. If the
trailer has electric brakes, start the
combination moving and then apply
the trailer brake controller by hand
to be sure the brakes work.
During the trip, check occasionally
to be sure that the load is secure
and the lamps and any trailer
brakes still work.
Following Distance
Stay at least twice as far behind the
vehicle ahead as you would when
driving the vehicle without a trailer.
This can help to avoid heavy
braking and sudden turns.
Passing
More passing distance is needed
when towing a trailer. The
combination will not accelerate
as quickly and is longer so it is
necessary to go much farther
beyond the passed vehicle before
returning to the lane.
Page 352 of 556
Black plate (76,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-76 Driving and Operating
Backing Up
Hold the bottom of the steering
wheel with one hand. To move the
trailer to the left, move that hand to
the left. To move the trailer to the
right, move your hand to the right.
Always back up slowly and,
if possible, have someone
guide you.
Making Turns
Notice:Making very sharp turns
while trailering could cause the
trailer to come in contact with the
vehicle. The vehicle could be
damaged. Avoid making very
sharp turns while trailering.
When turning with a trailer, make
wider turns than normal. Do this
so the trailer will not strike soft
shoulders, curbs, road signs, trees,
or other objects. Avoid jerky or
sudden maneuvers. Signal well in
advance. If the trailer turn signal bulbs burn
out, the arrows on the instrument
panel will still flash for turns. It is
important to check occasionally to
be sure the trailer bulbs are still
working.
Driving on Grades
Reduce speed and shift to a
lower gear
beforestarting down a
long or steep downgrade. If the
transmission is not shifted down, the
brakes might 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.
See Tow/Haul Mode on page 9‑39.
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 10‑22.
Parking on Hills
{WARNING
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 flat surface.
Page 353 of 556
Black plate (77,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-77
If parking the rig on a hill:
1. Press the brake pedal, but donot 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. Reapply the brake pedal. Then apply the parking brake and shift
into P (Park).
5. If the vehicle is four-wheel-drive, be sure the transfer case is in a
drive gear and not in N (Neutral).
6. Release the brake pedal.{WARNING
It can be dangerous to get out of
the vehicle if the shift lever is not
fully in P (Park) with the parking
brake firmly set. The vehicle
can roll.
If the engine has been left
running, the vehicle can move
suddenly. You or others could be
injured. To be sure the vehicle will
not move, even when on fairly
level ground, use the steps that
follow.
Always put the shift lever fully in
P (Park) with the parking brake
firmly set. (Continued)
WARNING (Continued)
If the transfer case on a
four-wheel-drive vehicle is in
N (Neutral), the vehicle will be
free to roll, even if the shift lever
is in P (Park). Be sure the transfer
case is in a drive gear —not in
N (Neutral).
Leaving After Parking on a Hill
1. Apply and hold the brake pedal.
2. Start the engine.
3. Shift into a gear.
4. Release the parking brake.
5. Let up on the brake pedal.
6. Drive slowly until the trailer is clear of the chocks.
7. Stop and have someone pick up and store the chocks.
Page 354 of 556
Black plate (78,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-78 Driving and Operating
Maintenance when Trailer
Towing
The vehicle needs service more
often when pulling a trailer. See
Maintenance Schedule on
page 11‑3. 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 Towing
If the vehicle has a diesel engine,
see the Duramax diesel supplement
for more information.
If the vehicle is a hybrid, see the
hybrid supplement for more
information.
Do not tow a trailer during break-in.
SeeNew Vehicle Break-In on
page 9‑25 for more information.{WARNING
The driver can lose control when
pulling a trailer if the correct
equipment is not used or the
vehicle is not driven properly.
For example, if the trailer is too
heavy, the brakes may not work
well or even at all. The driver and
passengers could be seriously
injured. The vehicle may also be
damaged; the resulting repairs
would not be covered by the
vehicle warranty. Pull a trailer
only if all the steps in this section
have been followed. Ask your
dealer for advice and information
about towing a trailer with the
vehicle.
Page 371 of 556
Black plate (95,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-95
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” underTrailer Towing on
page 9‑78 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.
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 2 271 kg
(5,000 lbs) 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.
Trailer Brakes
A loaded trailer that weighs more
than 900 kg (2,000 lbs) needs to
have its own brake system that is
adequate for the weight of the
trailer. Be sure to read and follow
the instructions for the trailer brakes
so they are installed, adjusted, and
maintained properly.
Do not tap into the vehicle's
hydraulic brake system.
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 driver
side of the vehicle, next to the
underhood electrical center.
Page 373 of 556
Black plate (97,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-97
.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 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 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 driver 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
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, a seven-wire
harness with a seven-pin connector
is located at the rear of the vehicle
and is tied to the vehicle's frame.
Page 374 of 556
Black plate (98,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-98 Driving and Operating
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
The harness should be installed by
your dealer or a qualified service
center.
If the vehicle is equipped with an
Integrated Trailer Brake Control
(ITBC) System, 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.
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 9‑39 for 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” under
Trailer Towing on page 9‑78. Tow/
Haul is most useful under the
following driving conditions:
.When pulling a heavy trailer or
a large or heavy load through
rolling terrain.