
Black plate (6,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
5-6 Instruments and Controls The power outlets on the center
stack and in front of the cupholders
are powered at all times. The power
outlets inside the storage area and
on the rear of the console are
powered when the ignition is in ON/
RUN or ACC/ACCESSORY,
or when RAP is active.
{ WarningPower is always supplied to the
outlets. Do not leave electrical
equipment plugged in when the
vehicle is not in use because the
vehicle could catch fire and cause
injury or death.
{ Caution
Leaving electrical equipment
plugged in for an extended period
of time while the vehicle is off will
drain the battery. Always unplug
electrical equipment when not in
(Continued) Caution (Continued) use and do not plug in equipment
that exceeds the maximum
15 amp rating.
Certain power accessory plugs may
not be compatible with the
accessory power outlet and could
overload vehicle or adapter fuses.
If a problem is experienced, see
your dealer.
When adding electrical equipment,
be sure to follow the proper
installation instructions included with
the equipment. See Add-On
Electrical Equipment on page 9-88 .{ CautionHanging heavy equipment from
the power outlet can cause
damage not covered by the
vehicle warranty. The power
outlets are designed for
accessory power plugs only, such
as cell phone charge cords. 

Black plate (7,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Instruments and Controls 5-7Power Outlet 110 Volt
Alternating Current
Base Shown, Uplevel Similar
If equipped with this power outlet, it
can be used to plug in electrical
equipment that uses a maximum
limit of 150 watts.
For vehicles with a center console,
the 110 volt power outlet is in front
of the cupholders in the center
console.
For vehicles with bench seats, the
110 volt power outlet is on the
center stack. An indicator light on the outlet turns
on to show it is in use. The light
comes on when the ignition is in
ON/RUN, equipment requiring less
than 150 watts is plugged into the
outlet, and no system fault is
detected.
The indicator light does not come on
when the ignition is in LOCK/OFF or
if the equipment is not fully seated
into the outlet.
If equipment is connected using
more than 150 watts or a system
fault is detected, a protection circuit
shuts off the power supply and the
indicator light turns off. To reset the
circuit, unplug the item and plug it
back in or turn the Retained
Accessory Power (RAP) off and
then back on. See Retained
Accessory Power (RAP) on
page 9-29 . The power outlet is not designed for
the following, and may not work
properly if they are plugged in: .
Equipment with high initial peak
wattage, such as
compressor-driven refrigerators
and electric power tools. .
Other equipment requiring an
extremely stable power supply,
such as
microcomputer-controlled
electric blankets and touch
sensor lamps. .
Medical equipment. 

Black plate (17,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Instruments and Controls 5-17
{ WarningIf the airbag readiness light stays
on after the vehicle is started or
comes on while driving, it means
the airbag system might not be
working properly. The airbags in
the vehicle might not inflate in a
crash, or they could even inflate
without a crash. To help avoid
injury, have the vehicle serviced
right away.
If there is a problem with the airbag
system, a Driver Information Center
(DIC) message may also come on.
See Airbag System Messages on
page 5-37 .
Passenger Airbag Status
Indicator The vehicle may have a passenger
sensing system. See Passenger
Sensing System on page 3-24 for important safety information. The
overhead console has a passenger
airbag status indicator.
United States
Canada and Mexico
When the vehicle is started, the
passenger airbag status indicator
will light ON and OFF, or the symbol
for on and off, for several seconds
as a system check. Then, after
several more seconds, the status
indicator will light either ON or OFF,
or either the on or off symbol to let you know the status of the front
outboard passenger frontal airbag.
If the word ON or the on symbol is
lit on the passenger airbag status
indicator, it means that the front
outboard passenger frontal airbag is
enabled (may inflate).
If the word OFF or the off symbol is
lit on the airbag status indicator, it
means that the passenger sensing
system has turned off the front
outboard passenger frontal airbag.
If, after several seconds, both status
indicator lights remain on, or if there
are no lights at all, there may be a
problem with the lights or the
passenger sensing system. See
your dealer for service.
{ Warning
If the airbag readiness light ever
comes on and stays on, it means
that something may be wrong
with the airbag system. To help
(Continued) 

Black plate (5,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Lighting 6-5one second will cause the turn
signals to flash until the lever is
released.
The lever returns to its starting
position whenever it is released.
If after signaling a turn or a lane
change the arrows flash rapidly or
do not come on, a signal bulb could
be burned out.
Replace any burned out bulbs. If a
bulb is not burned out, check the
fuse. See Fuses on page 10-41 .
Turn Signal On Chime
If the turn signal is left on for more
than 1.2 km (0.75 mi), a chime
sounds at each flash of the turn
signal. The message TURN
SIGNAL ON will also appear in the
Driver Information Center (DIC). To
turn the chime and message off,
move the turn signal lever to the off
position. Fog Lamps
The fog lamp control is on the
center of the exterior lamp control,
to the left of the steering column.
The ignition must be on for the fog
lamps to come on.
# (Fog Lamps): Press to turn the
fog lamps on or off. A light will come
on in the instrument cluster.
When the fog lamps are turned on,
the parking lamps automatically
turn on. When the headlamps are changed
to high beam, the fog lamps also go
off. When the high-beam headlamps
are turned off, the fog lamps will
come on again.
Some localities have laws that
require the headlamps to be on with
the fog lamps.
Auxiliary
Roof-Mounted Lamp If equipped, this button includes
wiring provisions for a dealer or a
qualified service center to install an
auxiliary roof lamp.
This button is on the overhead
console. 

Black plate (29,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-29Warning (Continued) vehicle. Possible heater cord
and thermostat damage could
occur. .
While in use, do not let the
heater cord touch vehicle
parts or sharp edges. Never
close the hood on the
heater cord. .
Before starting the vehicle,
unplug the cord, reattach the
cover to the plug, and
securely fasten the cord.
Keep the cord away from any
moving parts.
4. Before starting the engine, be
sure to unplug and store the
cord as it was before to keep it
away from moving engine parts.
If you do not, it could be
damaged. The length of time the heater should
remain plugged in depends on
several factors. Ask a dealer in the
area where you will be parking the
vehicle for the best advice on this.
Retained Accessory
Power (RAP) The following vehicle accessories
can be used for up to 10 minutes
after the engine is turned off: .
Audio System .
Power Windows .
OnStar System (if equipped) .
Sunroof (if equipped)
These features work when the key
is in ON/RUN or ACC/
ACCESSORY. Once the key is
turned from ON/RUN to LOCK/OFF,
the windows and sunroof continue
to work up to 10 minutes or until any
door is opened. The radio continues
to work for up to 10 minutes or until
the driver door is opened. Accessory Power Outlets (APOs)
The vehicle may have APOs in
several locations. See Power
Outlets on page 5-5 .
The APOs in the console or center
seat position are powered by RAP.
They will continue to work for up to
10 minutes after the key is turned
from ON/RUN to LOCK/OFF, or until
the driver door is opened.
The APOs on the center stack come
from the factory powered directly
from the vehicle battery, and supply
accessory power at all times,
regardless of ignition key position.
If electronic items are left plugged
into these APOs for long periods of
time with the vehicle off, the vehicle
battery could be drained. The
vehicle may not start if the battery is
allowed to drain for an extended
period of time. 

Black plate (2,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
i-2 INDEX
BBattery . . . . . . . . . . . . . . . . . . . . . . . 10-29
Jump Starting . . . . . . . . . . . . . . . 10-87
Load Management . . . . . . . . . . . . . 6-8
Power Protection . . . . . . . . . . . . . . 6-9
Voltage and Charging
Messages . . . . . . . . . . . . . . . . . . . 5-31
Blade Replacement, Wiper . . . 10-35
Blind Spot Mirrors . . . . . . . . . . . . . 2-17
Brake
Pedal and Adjustable
Throttle . . . . . . . . . . . . . . . . . . . . . . 9-23
System Warning Light . . . . . . . . 5-21
Brakes . . . . . . . . . . . . . . . . . . . . . . . . 10-26
Antilock . . . . . . . . . . . . . . . . . . . . . . . 9-46
Assist . . . . . . . . . . . . . . . . . . . . . . . . . 9-48
Fluid . . . . . . . . . . . . . . . . . . . . . . . . 10-27
Parking . . . . . . . . . . . . . . . . . . . . . . . 9-47
System Messages . . . . . . . . . . . . 5-32
Braking . . . . . . . . . . . . . . . . . . . . . . . . . 9-3
Break-In, New Vehicle . . . . . . . . . 9-23 Bulb Replacement . . . . . . . . . . . . 10-40
Center High-Mounted
Stoplamp (CHMSL) and
Cargo Lamp . . . . . . . . . . . . . . . 10-39
Halogen Bulbs . . . . . . . . . . . . . . 10-36
Headlamp Aiming . . . . . . . . . . . 10-36
Headlamps . . . . . . . . . . . . . . . . . 10-36
Headlamps, Front Turn
Signal, Sidemarker, and
Parking Lamps . . . . . . . . . . . . 10-36
Taillamps, Turn Signal,
Stoplamps, and
Back-up Lamps . . . . . . . . . . . 10-37
Buying New Tires . . . . . . . . . . . . . 10-69
C Calibration . . . . . . . . . . . . . . . . . . . . . . 5-4
California
Fuel Requirements . . . . . . . . . . . 9-64
Perchlorate Materials
Requirements . . . . . . . . . . . . . . . 10-3
Warning . . . . . . . . . . . . . . . . . . . . . . 10-2
Canadian Vehicle Owners . . . . . . . . iii
Capacities and
Specifications . . . . . . . . . . . . . . . . 12-2 Carbon Monoxide
Engine Exhaust . . . . . . . . . . . . . . . 9-32
Tailgate . . . . . . . . . . . . . . . . . . . . . . . 2-10
Winter Driving . . . . . . . . . . . . . . . . 9-12
Cargo
Tie-Downs . . . . . . . . . . . . . . . . . . . . . 4-3
Cargo Lamp . . . . . . . . . . . . . . . . . . . . 6-6
Cautions, Danger, and
Warnings . . . . . . . . . . . . . . . . . . . . . . . . iv
Center Console Storage . . . . . . . . 4-2
Center High-Mounted
Stoplamp (CHMSL) and
Cargo Lamp . . . . . . . . . . . . . . . . . 10-39
Chains, Tire . . . . . . . . . . . . . . . . . . 10-74
Charging System Light . . . . . . . . 5-18
Check
Engine Light . . . . . . . . . . . . . . . . . . 5-18
Ignition
Transmission Lock . . . . . . . . 10-34 

Black plate (11,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
INDEX i-11Service . . . . . . . . . . . . . . . . . . . . . . . . . 8-6
Accessories and
Modifications . . . . . . . . . . . . . . . . 10-3
Doing Your Own Work . . . . . . . . 10-3
Engine Soon Light . . . . . . . . . . . . 5-18
Maintenance Records . . . . . . .11-16
Maintenance, General
Information . . . . . . . . . . . . . . . . . . 11-1
Parts Identification Label . . . . . 12-1
Publications Ordering
Information . . . . . . . . . . . . . . . . .13-11
Scheduling Appointments . . . . . 13-7
Services
Special Application . . . . . . . . . . . 11-8
Servicing the Airbag . . . . . . . . . . . 3-28
Shift Lock Control Function
Check, Automatic
Transmission . . . . . . . . . . . . . . . . 10-34
Shifting
Into Park . . . . . . . . . . . . . . . . . . . . . . 9-30
Out of Park . . . . . . . . . . . . . . . . . . . 9-31
Signals, Turn and
Lane-Change . . . . . . . . . . . . . . . . . 6-4
Snow Plow . . . . . . . . . . . . . . . . . . . . 9-88
Special Application Services . . . 11-8 Specifications and
Capacities . . . . . . . . . . . . . . . . . . . . 12-2
Speedometer . . . . . . . . . . . . . . . . . . 5-11
StabiliTrak
OFF Light . . . . . . . . . . . . . . . . . . . . . 5-23
Start Assist, Hills . . . . . . . . . . . . . . 9-48
Start Vehicle, Remote . . . . . . . . . . 2-7
Starter Switch Check . . . . . . . . . 10-33
Starting the Engine . . . . . . . . . . . . 9-26
Steering . . . . . . . . . . . . . . . . . . . . . . . . 9-4
Fluid, Power . . . . . . . . . . . . . . . . 10-24
Heated Wheel . . . . . . . . . . . . . . . . . 5-3
Wheel Adjustment . . . . . . . . . . . . . 5-2
Wheel Controls . . . . . . . . . . . . . . . . 5-2
Steering System Messages . . . . 5-38
Stoplamps and Back-up Lamps
Bulb Replacement . . . . . . . . . . 10-37
Storage Areas
Center Console . . . . . . . . . . . . . . . . 4-2
Floor Console . . . . . . . . . . . . . . . . . 4-3
Glove Box . . . . . . . . . . . . . . . . . . . . . 4-1
Instrument Panel . . . . . . . . . . . . . . 4-1
Sunglasses . . . . . . . . . . . . . . . . . . . . 4-2
Storage Compartments . . . . . . . . . 4-1
Stuck Vehicle . . . . . . . . . . . . . . . . . . 9-14
Sun Visors . . . . . . . . . . . . . . . . . . . . . 2-22 Sunglass Storage . . . . . . . . . . . . . . . 4-2
Sunroof . . . . . . . . . . . . . . . . . . . . . . . . 2-22
Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . iv
System
Forward Collision
Alert (FCA) . . . . . . . . . . . . . . . . . . 9-59
Infotainment . . . . . . . . . . . . 7-1, 13-15
Noise Control . . . . . . . . . . . . . . . 10-32
Systems
Driver Assistance . . . . . . . . . . . . . 9-55
T Tachometer . . . . . . . . . . . . . . . . . . . . 5-11
Tailgate . . . . . . . . . . . . . . . . . . . . . . . . 2-10
Taillamps
Bulb Replacement . . . . . . . . . . 10-37
Text Telephone (TTY) Users . . . 13-4
Theft-Deterrent Systems . . . . . . . 2-13
Immobilizer . . . . . . . . . . . . . . . . . . . 2-12
Throttle, Adjustable . . . . . . . . . . . . 9-23
Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 10-50
All-Season . . . . . . . . . . . . . . . . . . 10-51
All-Terrain . . . . . . . . . . . . . . . . . . 10-52
Buying New Tires . . . . . . . . . . . 10-69
Chains . . . . . . . . . . . . . . . . . . . . . . 10-74