2018 GMC SIERRA DENALI instrument panel

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 329
For vehicles with the fifth wheel/
gooseneck trailer package, the
harness connector is mounted on
the inside of the pickup bed behind
the rear wheel.
The seven-wire harness contains
the following trailer circuits:
.
Green/Violet: Right Stop/Turn
Signal
.
Yellow/Gray: Left Stop/Turn
Signal
.
Gray/Brown: Taillamps/Parking
Lamps
.
White/Green: Back-up Lamps
.
Red/Green: Battery Feed .
White: Ground
.
Blue: Electric Trailer Brake
To help charge a remote
(non-vehicle) battery, press the Tow/
Haul Mode button at the end of the
shift lever. If the trailer is too light for
Tow/Haul Mode, turn on the
headlamps to help charge the
battery.
Camper/Fifth-Wheel Trailer Wiring
Package
For vehicles without the fifth wheel/
gooseneck trailer package,
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: Right Stop/Turn
Signal
.
Yellow/Gray: Left Stop/Turn
Signal .
Gray/Brown: Taillamps/Parking
Lamps
.
White/Green: Back-up Lamps
.
Red/Green: Battery Feed
.
White: Ground
.
Blue: Electric Trailer Brake
If the vehicle is equipped with the
heavy-duty trailering option, see
“ Heavy-Duty Trailer Wiring Harness
Package ” earlier in this section.
Electric Brake Control Wiring
Provisions Wiring provisions for an electric
trailer brake controller are included
with the vehicle as part of the trailer
wiring package. The instrument
panel contains blunt cut wires above
the parking brake assembly for the
electric trailer brake controller.
The harness contains the following
circuits:
.
Blue: Electric Trailer Brakes
.
Red/Black or Red/Blue:
Battery Feed
.
White/Blue: Brake Apply Signal

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 331
This symbol is on the Trailer Brake
Control Panel on vehicles with an
ITBC system. The power output to
the trailer brakes is based on the
amount of brake pressure being
applied by the vehicle ’ s brake
system, and on the type of trailer
brakes detected. This available
power output to the trailer brakes
can be adjusted to a wide range of
trailering situations.
The ITBC system is integrated with
the vehicle ’ s brake, antilock brake,
and StabiliTrak systems. In trailering
conditions that cause the vehicle ’ s
antilock brake or StabiliTrak
systems to activate, power sent to
the trailer's brakes will be
automatically adjusted to minimize
trailer wheel lock-up. This does not
imply that the trailer has StabiliTrak. If the vehicle ’ s brake, antilock brake,
or StabiliTrak systems are not
functioning properly, the ITBC
system may not be fully functional
or may not function at all. Make sure
all of these systems are fully
operational to ensure full
functionality of the ITBC system.
The ITBC system is powered
through the vehicle's electrical
system. Turning the ignition off will
also turn off the ITBC system. The
ITBC system is fully functional only
when the ignition is in ON/RUN.
{ WarningConnecting a trailer that has an
air brake system may result in
reduced or complete loss of trailer
braking. There may be an
increase in stopping distance or
trailer instability which could
result in personal injury or
damage to the vehicle, trailer,
or other property. Use the ITBC
(Continued) Warning (Continued) system only with electric or
electric over hydraulic trailer
brakes.
Trailer Brake Control Panel
1. Manual Trailer Brake Apply
Lever
2. Trailer Gain Adjustment
Buttons
The ITBC system has a control
panel on the instrument panel to the
left of the steering column. See
Instrument Panel 0 6 . The control

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Vehicle Care 341
Vehicle Care General Information General Information . . . . . . . . . . 342
California Proposition
65 Warning . . . . . . . . . . . . . . . . . 343
California Perchlorate
Materials Requirements . . . . . 343
Accessories and
Modifications . . . . . . . . . . . . . . . . 343
Vehicle Checks Doing Your Own
Service Work . . . . . . . . . . . . . . . 344
Hood . . . . . . . . . . . . . . . . . . . . . . . . . 344
Engine Compartment
Overview . . . . . . . . . . . . . . . . . . . . 345
Engine Oil . . . . . . . . . . . . . . . . . . . . 350
Engine Oil Life System . . . . . . . 353
Automatic Transmission Fluid
(6-Speed Transmission) . . . . . 354
Automatic Transmission Fluid
(8-Speed Transmission) . . . . . 357
Engine Air Cleaner/Filter . . . . . . 358
Cooling System . . . . . . . . . . . . . . 359
Engine Overheating . . . . . . . . . . 363
Overheated Engine Protection
Operating Mode . . . . . . . . . . . . . 364
Engine Fan . . . . . . . . . . . . . . . . . . . 365 Power Steering Fluid (1500
Series) . . . . . . . . . . . . . . . . . . . . . . 365
Power Steering Fluid (2500/
3500 Series) . . . . . . . . . . . . . . . . 365
Washer Fluid . . . . . . . . . . . . . . . . . 366
Brakes . . . . . . . . . . . . . . . . . . . . . . . 367
Brake Fluid . . . . . . . . . . . . . . . . . . . 368
Battery - North America . . . . . . 369
Four-Wheel Drive . . . . . . . . . . . . . 370
Front Axle . . . . . . . . . . . . . . . . . . . . 370
Rear Axle . . . . . . . . . . . . . . . . . . . . 371
Noise Control System . . . . . . . . 373
Starter Switch Check . . . . . . . . . 374
Automatic Transmission Shift
Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . . . 374
Ignition Transmission Lock
Check . . . . . . . . . . . . . . . . . . . . . . . 374
Park Brake and P (Park)
Mechanism Check . . . . . . . . . . 375
Wiper Blade Replacement . . . . 375
Windshield Replacement . . . . . 376
Gas Strut(s) . . . . . . . . . . . . . . . . . . 376
Headlamp Aiming Headlamp Aiming . . . . . . . . . . . . 377
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . 378
Halogen Bulbs . . . . . . . . . . . . . . . . 378 High Intensity Discharge (HID)
Lighting . . . . . . . . . . . . . . . . . . . . . 378
LED Lighting . . . . . . . . . . . . . . . . . 378
Taillamps, Turn Signal,
Stoplamps, and Back-Up
Lamps . . . . . . . . . . . . . . . . . . . . . . 378
Center High-Mounted
Stoplamp (CHMSL) and
Cargo Lamp . . . . . . . . . . . . . . . . . 380
Electrical System High Voltage Devices and
Wiring . . . . . . . . . . . . . . . . . . . . . . . 380
Electrical System Overload . . . 380
Fuses and Circuit Breakers . . . 381
Engine Compartment Fuse
Block . . . . . . . . . . . . . . . . . . . . . . . . 381
Instrument Panel Fuse Block
(Right) . . . . . . . . . . . . . . . . . . . . . . 385
Instrument Panel Fuse
Block (Left) . . . . . . . . . . . . . . . . . 386
Wheels and Tires Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 389
All-Season Tires . . . . . . . . . . . . . . 389
Winter Tires . . . . . . . . . . . . . . . . . . 390
Low-Profile Tires . . . . . . . . . . . . . 390
All-Terrain Tires . . . . . . . . . . . . . . . 391
Tire Sidewall Labeling . . . . . . . . 391
Tire Designations . . . . . . . . . . . . . 393

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
380 Vehicle Care
Center High-Mounted
Stoplamp (CHMSL) and
Cargo Lamp
1. Cargo Lamp Bulbs
2. Center High-Mounted
Stoplamp (CHMSL) Bulb To replace one of these bulbs:
1. Remove the two screws and lift
off the lamp assembly.
2. Turn the bulb socket
counterclockwise and pull it
straight out.
3. Pull the bulb straight out from
the socket. Electrical System High Voltage Devices and
Wiring For an eAssist vehicle, see the
Silverado/Sierra eAssist
supplement.
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 left 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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
382 Vehicle Care Lift the cover to access the fuse
block.
CautionSpilling liquid on any electrical
component on the vehicle may
damage it. Always keep the
covers on any electrical
component.
A fuse puller is available in the left
instrument panel fuse block.
The vehicle may not be equipped
with all of the fuses, relays, and
features shown.
Fuses Usage
1 Trailer brake Fuses Usage
2 Trailer battery

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Vehicle Care 383Fuses Usage
3 Antilock brake
system pump
4 Instrument
panel BEC 1
5 Passenger
motorized seat belt
6 4WD transfer case
electronic control
7 Electric park brake
8 Instrument
panel BEC 2
9 Driver motorized
seat belt
10 Rear window
defogger
11 Starter
12 Cooling fan 1
13 Cooling fan 2
14 Left trailer stop/
Turn signal lamps
15 Trailer parking
lamps Fuses Usage
16 Trailer reverse
lamps
17 Right trailer stop/
Turn signal lamps
18 Fuel pump
19 Integrated chassis
control module
20 Electronic
suspension control
module
21 Fuel pump power
module
22 Upfitter 1
23 Upfitter 2
24 Front wiper
25 Antilock brake
system valve
26 Upfitter 2
27 Upfitter 3
28 Right parking
lamps
29 Left parking lamps Fuses Usage
30 Upfitter 3
31 Upfitter 4
32 Upfitter 4
33 Reverse lamps
34 Engine control
module/Ignition
35 Air conditioning
clutch
36 Heated mirrors
37 Upfitter 1
38 Center
high-mounted
stoplamp
39 Miscellaneous/
Ignition
40 Transmission/
Ignition
41 Fuel pump 2
42 Cooling fan clutch
43 Engine
44 Fuel
injectors A – odd

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Vehicle Care 385
Instrument Panel Fuse
Block (Right)
The right instrument panel fuse
block access door is on the
passenger side edge of the
instrument panel.
Pull off the cover to access the fuse
block.
The vehicle may not be equipped
with all of the fuses, relays, and
features shown. Fuses Usage
1 Accessory power
outlet 3

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
386 Vehicle Care Fuses Usage
2 Accessory power
outlet 4
7 Body control module 4
8 Body control module 8
9 Rear seat
entertainment
10 Cargo lamp
15 Steering wheel
controls
18 Radio
19 –
20 Sunroof
23 Airbag/Info
26 Export/Power take off/
Special equipment
option/Battery 1
27 Obstacle detection/
USB ports
28 Body control module 2
32 Special equipment
option/Battery 2 Fuses Usage
35 Air conditioning
inverter
36 Amplifier
37 Battery system
39 Rear sliding window
42 Right door window
motor
43 Front blower
44 Special equipment
option
45 Body control module 6
46 Body control module 7
47 Passenger seat
Relays Usage
50 Retained accessory
power
51 Rear sliding
window open
52 Rear sliding window
close Instrument Panel Fuse
Block (Left)
The left instrument panel fuse block
access door is on the driver side
edge of the instrument panel.
Pull off the cover to access the fuse
block.