2015 GMC SIERRA DENALI turn signal

Black plate (81,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-81Basic Trailer Wiring
All regular, double 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.
Heavy-Duty Trailer Wiring Harness
Package For vehicles equipped with
heavy-duty trailering, the harness
connector is mounted in the bumper.
The seven-wire harness contains
the following trailer circuits: .
Green/Violet: Left Stop/Turn
Signal .
Yellow/Gray: Right Stop/Turn
Signal .
Gray/Brown: Taillamps/Parking
Lamps .
White: Ground .
White/Green: Back-up Lamps .
Red/Green: Battery Feed .
Dark Blue: Trailer Brake
If charging a remote (non-vehicle)
battery, press the Tow/Haul Mode
button, if equipped, 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
under the rear bumper, attached to
the frame near the rear
crossmember. A connector must be
added to the wiring harness that
connects to the camper.
The harness contains the following
camper/trailer circuits: .
Green/Violet: Left Stop/Turn
Signal .
Yellow/Gray: Right Stop/Turn
Signal .
Gray/Brown: Taillamps/Parking
Lamps .
White: Ground .
White/Green: Back-up Lamps .
Red/Green: Battery Feed .
Dark Blue: Trailer Brake

Black plate (1,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-1
Vehicle Care General Information General Information . . . . . . . . . . 10-2
California Proposition
65 Warning . . . . . . . . . . . . . . . . . 10-2
California Perchlorate
Materials Requirements . . . . 10-3
Accessories and
Modifications . . . . . . . . . . . . . . . 10-3
Vehicle Checks Doing Your Own
Service Work . . . . . . . . . . . . . . . 10-3
Hood . . . . . . . . . . . . . . . . . . . . . . . . 10-4
Engine Compartment
Overview . . . . . . . . . . . . . . . . . . . 10-5
Engine Oil . . . . . . . . . . . . . . . . . . . 10-8
Engine Oil Life System . . . . . 10-11
Automatic Transmission
Fluid (6 Speed
Transmission) . . . . . . . . . . . . . 10-12
Automatic Transmission
Fluid (8 Speed
Transmission) . . . . . . . . . . . . . 10-15
Engine Air Cleaner/Filter . . . . 10-15
Cooling System . . . . . . . . . . . . 10-17
Engine Coolant . . . . . . . . . . . . . 10-18 Engine Overheating . . . . . . . . 10-21
Overheated Engine
Protection
Operating Mode . . . . . . . . . . . 10-23
Engine Fan . . . . . . . . . . . . . . . . . 10-24
Power Steering Fluid (1500
Series) . . . . . . . . . . . . . . . . . . . . 10-24
Power Steering Fluid (2500/
3500 Series) . . . . . . . . . . . . . . 10-24
Washer Fluid . . . . . . . . . . . . . . . 10-25
Brakes . . . . . . . . . . . . . . . . . . . . . 10-26
Brake Fluid . . . . . . . . . . . . . . . . . 10-27
Battery . . . . . . . . . . . . . . . . . . . . . 10-29
Four-Wheel Drive . . . . . . . . . . . 10-29
Front Axle . . . . . . . . . . . . . . . . . . 10-30
Rear Axle . . . . . . . . . . . . . . . . . . 10-31
Noise Control System . . . . . . 10-32
Starter Switch Check . . . . . . . 10-33
Automatic Transmission Shift
Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . 10-34
Ignition Transmission Lock
Check . . . . . . . . . . . . . . . . . . . . . 10-34
Park Brake and P (Park)
Mechanism Check . . . . . . . . 10-34
Wiper Blade
Replacement . . . . . . . . . . . . . . 10-35
Glass Replacement . . . . . . . . 10-35 Headlamp Aiming Headlamp Aiming . . . . . . . . . . 10-36
Bulb Replacement Bulb Replacement . . . . . . . . . . 10-36
Halogen Bulbs . . . . . . . . . . . . . . 10-36
LED Lighting . . . . . . . . . . . . . . . 10-36
Headlamps, Front Turn
Signal, Sidemarker, and
Parking Lamps . . . . . . . . . . . . 10-36
Fog Lamps . . . . . . . . . . . . . . . . . 10-37
Taillamps, Turn Signal,
Stoplamps, and Back-Up
Lamps . . . . . . . . . . . . . . . . . . . . 10-37
Center High-Mounted
Stoplamp (CHMSL) and
Cargo Lamp . . . . . . . . . . . . . . 10-39
Replacement Bulbs . . . . . . . . . 10-40
Electrical System Electrical System
Overload . . . . . . . . . . . . . . . . . . 10-40
Fuses . . . . . . . . . . . . . . . . . . . . . . 10-41
Engine Compartment Fuse
Block . . . . . . . . . . . . . . . . . . . . . 10-41
Instrument Panel Fuse
Block (Left) . . . . . . . . . . . . . . . 10-45
Instrument Panel Fuse Block
(Right) . . . . . . . . . . . . . . . . . . . . 10-48

Black plate (36,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
10-36 Vehicle Care
Headlamp Aiming Headlamp aim has been preset and
should need no further adjustment.
If the vehicle is damaged in a crash,
the headlamp aim may be affected.
If adjustment to the headlamps is
necessary, see your dealer.
Bulb Replacement For the proper type of replacement
bulbs, see Replacement Bulbs on
page 10-40 .
For any bulb ‐ changing procedure
not listed in this section, contact
your dealer.
Halogen Bulbs
{ WarningHalogen bulbs have pressurized
gas inside and can burst if you
drop or scratch the bulb. You or
others could be injured. Be sure
to read and follow the instructions
on the bulb package.
LED Lighting This vehicle has several LED lamps.
For replacement of any LED lighting
assembly, contact your dealer. Headlamps, Front Turn
Signal, Sidemarker, and
Parking Lamps
Driver Side
1. Front Turn Signal/
Sidemarker/Parking Lamp
2. High/Low-Beam Headlamp
See your dealer for passenger side
replacement.
Headlamp
1. Open the hood.

Black plate (37,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-372. Remove the headlamp bulb
assembly cover by turning it
counterclockwise.
3. Turn the bulb socket
counterclockwise to remove it
from the headlamp assembly
and pull it straight out.
4. Unplug the electrical connector
from the old bulb by releasing
the clip on the bulb socket.
Turn Signal/Sidemarker/
Parking Lamp 1. Open the hood.
2. If replacing a bulb on the
passenger side, remove the
engine air cleaner.
3. Turn the bulb socket
counterclockwise to remove it
from the headlamp assembly
and pull it straight out.
4. Remove the bulb by pulling it
straight out of the bulb socket. Fog Lamps To replace the front fog lamp bulb:
1. Locate the fog lamp under the
front bumper.
2. Disconnect the electrical
connector from the fog lamp bulb
assembly by pressing the
connector release.
3. Remove the bulb from the
housing by squeezing the two
release tabs and pulling it
straight out of the assembly. Taillamps, Turn Signal,
Stoplamps, and Back-Up
Lamps
Single Rear Wheel Lamp Shown,
Dual Rear Wheel Lamp Similar
1. Stoplamp/Taillamp/Turn
Signal Lamp
2. Back-Up Lamp
3. Sidemarker Lamp
To replace one of these bulbs:
1. Open the tailgate.

Black plate (40,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
10-40 Vehicle Care
Replacement Bulbs Exterior Lamp Bulb
Number
Back-Up Lamp 921 (W16W)
Back-Up Lamp* 1156
Cargo Lamp 921 (W16W)
Center
High-Mounted
Stoplamp
(CHMSL) 921LL
Fog Lamp PS24W
Front Turn Signal
Lamp and
Parking Lamp 7443 LL
High/Low-Beam
Headlamp HIR – 2
(9012 LL)
Rear
Sidemarker Lamp 194 Exterior Lamp Bulb
Number
Stoplamp/Taillamp/
Turn Signal Lamp 7444 LL
Stoplamp/Turn
Signal Lamp/
Taillamp* 1157
* Chassis Cab Models
For replacement bulbs not listed
here, contact your dealer.
Electrical System Electrical System
Overload The vehicle has fuses to protect
against an electrical system
overload. Fuses also protect power
devices in the vehicle.
Replace a bad fuse with a new one
of the identical size and rating.
If there is a problem on the road and
a fuse needs to be replaced, there
are some spare fuses and a fuse
puller in the Instrument Panel Fuse
Block. The same amperage fuse
can also be borrowed. Choose
some feature of the vehicle that is
not needed to use and replace it as
soon as possible.
Headlamp Wiring
An electrical overload may cause
the lamps to go on and off, or in
some cases to remain off. Have the

Black plate (61,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-61Return the tires to the
recommended cold tire inflation
pressure when high-speed driving
has ended. See Vehicle Load Limits
on page 9-15 and Tire Pressure on
page 10-59 .
Tire Pressure Monitor
System The Tire Pressure Monitor System
(TPMS) uses radio and sensor
technology to check tire pressure
levels. The TPMS sensors monitor
the air pressure in your tires and
transmit tire pressure readings to a
receiver located in the vehicle.
Each tire, including the spare (if
provided), should be checked
monthly when cold and inflated to
the inflation pressure recommended
by the vehicle manufacturer on the
vehicle placard or tire inflation
pressure label. (If your vehicle has
tires of a different size than the size
indicated on the vehicle placard or tire inflation pressure label, you
should determine the proper tire
inflation pressure for those tires.)
As an added safety feature, your
vehicle has been equipped with a
tire pressure monitoring system
(TPMS) that illuminates a low tire
pressure telltale when one or more
of your tires is significantly
under-inflated.
Accordingly, when the low tire
pressure telltale illuminates, you
should stop and check your tires as
soon as possible, and inflate them
to the proper pressure. Driving on a
significantly under-inflated tire
causes the tire to overheat and can
lead to tire failure. Under-inflation
also reduces fuel efficiency and tire
tread life, and may affect the
vehicle's handling and stopping
ability.
Please note that the TPMS is not a
substitute for proper tire
maintenance, and it is the driver's
responsibility to maintain correct tire
pressure, even if under-inflation has not reached the level to trigger
illumination of the TPMS low tire
pressure telltale.
Your vehicle has also been
equipped with a TPMS malfunction
indicator to indicate when the
system is not operating properly.
The TPMS malfunction indicator is
combined with the low tire pressure
telltale. When the system detects a
malfunction, the telltale will flash for
approximately one minute and then
remain continuously illuminated.
This sequence will continue upon
subsequent vehicle start-ups as
long as the malfunction exists.
When the malfunction indicator is
illuminated, the system may not be
able to detect or signal low tire
pressure as intended. TPMS
malfunctions may occur for a variety
of reasons, including the installation
of replacement or alternate tires or
wheels on the vehicle that prevent
the TPMS from functioning properly.
Always check the TPMS malfunction
telltale after replacing one or more
tires or wheels on your vehicle to

Black plate (64,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
10-64 Vehicle Care .
Replacement tires or wheels do
not match the original equipment
tires or wheels. Tires and wheels
other than those recommended
could prevent the TPMS from
functioning properly. See Buying
New Tires on page 10-69 ..
Operating electronic devices or
being near facilities using radio
wave frequencies similar to the
TPMS could cause the TPMS
sensors to malfunction.
If the TPMS is not functioning
properly, it cannot detect or signal a
low tire condition. See your dealer
for service if the TPMS malfunction
light and DIC message come on
and stay on.
TPMS Sensor Matching
Process
Each TPMS sensor has a unique
identification code. The identification
code needs to be matched to a new
tire/wheel position after rotating the
vehicle ’ s tires or replacing one or
more of the TPMS sensors. Also,
the TPMS sensor matching process should be performed after replacing
a spare tire with a road tire
containing the TPMS sensor. The
malfunction light and the DIC
message should go off at the next
ignition cycle. The sensors are
matched to the tire/wheel positions,
using a TPMS relearn tool, in the
following order: driver side front tire,
passenger side front tire, passenger
side rear tire, and driver side rear.
See your dealer for service or to
purchase a relearn tool. A TPMS
relearn tool can also be purchased.
See Tire Pressure Monitor
Sensor Activation Tool at
www.gmtoolsandequipment.com or
call 1-800-GM TOOLS
(1-800-468-6657).
There are two minutes to match the
first tire/wheel position, and
five minutes overall to match all four
tire/wheel positions. If it takes
longer, the matching process stops
and must be restarted. The TPMS sensor matching
process is:
1. Set the parking brake.
2. Turn the ignition to ON/RUN with
the engine off.
3. Make sure the Tire Pressure info
page option is turned on. The
info pages on the DIC can be
turned on and off through the
Settings menu. See Driver
Information Center (DIC) on
page 5-27 .
4. Use the DIC controls on the right
side of the steering wheel to
scroll to the Tire Pressure
screen under the DIC info page.
5. Press and hold the
V (Set/
Reset) button located in the
center of the DIC controls.
The horn sounds twice to signal
the receiver is in relearn mode
and the TIRE LEARNING
ACTIVE message displays on
the DIC screen.

Black plate (7,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
OnStar 14-7in that area. The wireless service
provider must also have coverage,
network capacity, reception, and
technology compatible with OnStar
services. Service involving location
information about the vehicle cannot
work unless GPS signals are
available, unobstructed, and
compatible with the OnStar
hardware. OnStar services may not
work if the OnStar equipment is not
properly installed or it has not been
properly maintained. If equipment or
software is added, connected,
or modified, OnStar services may
not work. Other problems beyond
the control of OnStar may prevent
service such as hills, tall buildings,
tunnels, weather, electrical system
design and architecture of the
vehicle, damage to the vehicle in a
crash, or wireless phone network
congestion or jamming.
See Radio Frequency Statement on
page 13-12 . Services for People with
Disabilities Advisors provide services to help
subscribers with physical disabilities
and medical conditions.
Press
Q for help with: .
Locating a gas station with an
attendant to pump gas. .
Finding a hotel, restaurant, etc.,
that meets accessibility needs. .
Providing directions to the
closest hospital or pharmacy in
urgent situations.
TTY Users OnStar has the ability to
communicate to deaf,
hard-of-hearing, or speech-impaired
customers while in the vehicle. The
available dealer-installed TTY
system can provide in-vehicle
access to all of the OnStar services,
except Virtual Advisor and OnStar
Turn-by-Turn Navigation. OnStar Personal Identification
Number (PIN) A PIN is needed to access some of
the OnStar services, like Remote
Door Unlock and Stolen Vehicle
Assistance. The PIN will need to be
changed the first time when
speaking with an Advisor. To
change the OnStar PIN, contact an
OnStar Advisor by pressing
Q or
calling 1-888-4-ONSTAR.
Warranty OnStar equipment may be
warranted as part of the vehicle
warranty.
Languages The vehicle can be programmed to
respond in multiple languages.
Press
Q and ask for an Advisor.
Advisors are available in English,
Spanish, and French. Available
languages may vary by country.