
GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 255
Lighting Conditions Affecting ACC
The ACC front camera can be
affected by poor lighting conditions,
and ACC may have limited
performance when:
.There are changes in brightness,
such as entering and exiting
tunnels, bridges, and
overpasses.
. Low sun angles cause the
camera to not detect objects,
or it is more difficult to detect
objects in the same traffic lane.
. Lighting is poor in the evening or
early morning
. There are multiple changes in
brightness or shadows along the
vehicle roadway.
. In a tunnel without the
headlamps on, or in a tunnel
when there is a vehicle in front
that does not have its
taillamps on. .
Subjected to strong light from
opposing lane traffic in the front
of the vehicle, such as
high-beam headlamps from
oncoming traffic.
Accessory Installations and
Vehicle Modifications
Do not install or place any object
around the front camera windshield
area that would obstruct the front
camera view.
Do not install objects on top of the
vehicle that overhang and obstruct
the front camera, such as a canoe,
kayak, or other items that can be
transported on the vehicle roof.
Do not modify the hood, headlamps,
or fog lamps, as this may limit the
camera’s ability to detect an object.
Cleaning the Sensing System
The camera sensor on the
windshield behind the rearview
mirror can become blocked by
snow, ice, dirt, mud, or debris. This
area needs to be cleaned for ACC
to operate properly. The vehicle headlamps may need to
be cleaned due to dirt, snow, or ice.
Objects that are not illuminated
correctly may be difficult to detect.
If ACC will not operate, regular
cruise control may be available. See
“Switching Between ACC and
Regular Cruise Control”
previously
in this section. Always consider
driving conditions before using
either cruise control system.
For cleaning instructions, see
“Washing the Vehicle” under
Exterior Care 0429.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
372 Vehicle Care
FusesUsage
1 High-beam left Fuses
Usage
2 High-beam right
3 Headlamp left Fuses
Usage
4 Headlamp right
6 TIM
7 –
8 Fog lamp
9 VKM
10 –
11 Police upfitter
12 –
13 Washer front
14 Washer rear
15 MSB driver
16 –
17 IECL 1
19 DC/AC inverter
20 IECR 2 (LD) / EBCM2 (HD)
21 MSB pass
22 IECL 2
24 EBCM 1
25 REC

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/-
Mexico-13337776) - 2020 - CRC - 4/4/19
Index 493
Glove Box . . . . . . . . . . . . . . . . . . . . . . 113
GM Mobility ReimbursementProgram . . . . . . . . . . . . . . . . . . . . . . . 466
H
Halogen Bulbs . . . . . . . . . . . . . . . . . . 367
Hazard Warning Flashers . . . . . . . 169
Head Restraints . . . . . . . . . . . . . . . . . 54
Head-up Display . . . . . . . . . . . . . . . . 152
HeadlampsAiming . . . . . . . . . . . . . . . . . . . . . . . . 366
Automatic . . . . . . . . . . . . . . . . . . . . . 168
Bulb Replacement . . . . . . . . . . . . 367
Daytime RunningLamps (DRL) . . . . . . . . . . . . . . . . 168
Flash-to-Pass . . . . . . . . . . . . . . . . . 168
Headlamps, Front Turn Signal, Sidemarker, and
Parking Lamps . . . . . . . . . . . . . . 367
High-Beam On Light . . . . . . . . . . 147
High/Low Beam Changer . . . . . 167
Lamps On Reminder . . . . . . . . . 147
Heated Rear Seats . . . . . . . . . . . . . . . . . . . . . 64
Steering Wheel . . . . . . . . . . . . . . . 120
Heated and Ventilated Front
Seats . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Heated Mirrors . . . . . . . . . . . . . . . . . . . 44 Heater
Engine . . . . . . . . . . . . . . . . . . . . . . . . 215
Heating . . . . . . . . . . . . . . . . . . . . 177, 179
High-Beam On Light . . . . . . . . . . . . 147
High-Speed Operation . . . . . . . . . . 389
Hill and Mountain Roads . . . . . . . . 197
Hill Descent Control (HDC) . . . . . 237
Hill Descent Control Light . . . . . . . 142
Hill Start Assist (HSA) . . . . . . . . . . 235
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . 330
Horn . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
How to Wear Seat Belts Properly . . . . . . . . . . . . . . . . . . . . . . . . 66
HVAC . . . . . . . . . . . . . . . . . . . . . . 177, 179
I
Ignition Positions . . . . . . . . . . 208, 210
Ignition Transmission Lock Check . . . . . . . . . . . . . . . . . . . . . . . . . 363
Immobilizer . . . . . . . . . . . . . . . . . . . . . . 39
Indicator Pedestrian Ahead . . . . . . . . . . . . 143
Vehicle Ahead . . . . . . . . . . . . . . . . 143
Infants and Young Children, Restraints . . . . . . . . . . . . . . . . . . . . . . 87
Information
Publication Ordering . . . . . . . . . . 472
Infotainment . . . . . . . . . . . . . . . . . . . . 176 Infotainment System . . . . . . . . . . . . 476
Instrument Cluster . . . . . . . . . . . . . . 127
Instrument Panel Overview . . . . . . . 5
Interior Rearview Mirrors . . . . . . . . . 46
Introduction . . . . . . . . . . . . . . . . . . . . . . . 2
J
Jump Starting - North
America . . . . . . . . . . . . . . . . . . . . . . . 419
K
Keyless EntryRemote (RKE) System . . . . . 13, 15
Keys . . . . . . . . . . . . . . . . . . . . . . . . . . .9, 12
L
Labeling, Tire Sidewall . . . . . . . . . . 381
Lamps Daytime Running (DRL) . . . . . . 168
Dome . . . . . . . . . . . . . . . . . . . . . . . . . 172
Exterior Cargo . . . . . . . . . . . . . . . . 171
Exterior Controls . . . . . . . . . . . . . . 165
Exterior Lamps OffReminder . . . . . . . . . . . . . . . . . . . 167
Exterior Lighting Battery Saver . . . . . . . . . . . . . . . . . . . . . . . 174
License Plate . . . . . . . . . . . . . . . . . 369
Malfunction Indicator (Check Engine) . . . . . . . . . . . . . 138

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/-
Mexico-13337776) - 2020 - CRC - 4/4/19
494 Index
Lamps (cont'd)On Reminder . . . . . . . . . . . . . . . . . 147
Reading . . . . . . . . . . . . . . . . . . . . . . 173
Lane Change Alert (LCA) . . . . . . . 274
Lane Departure
Warning (LDW) . . . . . . . . . . . . . . . . 276
Lane Departure Warning Light . . . . . . . . . . . . . . . . . . . . . . . . . . 142
Lane Keep Assist (LKA) . . . . . . . . 278
Lane Keep Assist Light . . . . . . . . . 143
Lap-Shoulder Belt . . . . . . . . . . . . . . . 68
LATCH System
Replacing Parts after aCrash . . . . . . . . . . . . . . . . . . . . . . . 105
LATCH, Lower Anchors and Tethers for Children . . . . . . . . . . . . 92
LED Lighting . . . . . . . . . . . . . . . . . . . . 367
Lighting Entry . . . . . . . . . . . . . . . . . . . . . . . . . 173
Exit . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
Illumination Control . . . . . . . . . . . 172
LED . . . . . . . . . . . . . . . . . . . . . . . . . . 367
Task . . . . . . . . . . . . . . . . . . . . . . . . . . 171
Lights Airbag Readiness . . . . . . . . . . . . . 136
Antilock Brake System(ABS) Warning . . . . . . . . . . . . . . 141
Brake System Warning . . . . . . . 140 Lights (cont'd)
Charging System . . . . . . . . . . . . . 138
Check Engine (Malfunction
Indicator) . . . . . . . . . . . . . . . . . . . . 138
Cruise Control . . . . . . . . . . . . . . . . 147
Door Ajar . . . . . . . . . . . . . . . . . . . . . 148
Driver Mode Control . . . . . . . . . . 145
Electric Parking Brake . . . . . . . . 141
Electronic Stability Control (ESC), Off . . . . . . . . . . . . . . . . . . . 144
Engine Coolant Temperature Warning . . . . . . . 145
Engine Oil Pressure . . . . . . . . . . 146
Flash-to-Pass . . . . . . . . . . . . . . . . . 168
Four-Wheel-Drive . . . . . . . . . . . . . 142
Front Fog Lamp . . . . . . . . . . . . . . 147
High-Beam On . . . . . . . . . . . . . . . . 147
High/Low Beam Changer . . . . . 167
Hill Descent Control . . . . . . . . . . 142
Lane Departure Warning . . . . . . 142
Lane Keep Assist . . . . . . . . . . . . . 143
Low Fuel Warning . . . . . . . . . . . . 146
Seat Belt Reminders . . . . . . . . . . 136
Security . . . . . . . . . . . . . . . . . . . . . . 147
Service Electric Parking Brake . . . . . . . . . . . . . . . . . . . . . . . 141
Tire Pressure . . . . . . . . . . . . . . . . . 145
Tow/Haul Mode . . . . . . . . . . . . . . . 142 Lights (cont'd)
Traction Off . . . . . . . . . . . . . . . . . . . 143
Limited-Slip Differential . . . . . . . . . 242
Lock Steering Column . . . . . . . . . . . . . . . . 38
Locking Rear Axle . . . . . . . . . . . . . . 243
Locks Automatic Door . . . . . . . . . . . . . . . . . 26
Delayed Locking . . . . . . . . . . . . . . . . 26
Door . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Lockout Protection . . . . . . . . . . . . . . 27
Power Door . . . . . . . . . . . . . . . . . . . . . 26
Safety . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Loss of Control . . . . . . . . . . . . . . . . . 190
Low Fuel Warning Light . . . . . . . . . 146
Low-Profile Tires . . . . . . . . . . . . . . . . 380
Lower Anchors and Tethers for Children (LATCH
System) . . . . . . . . . . . . . . . . . . . . . . . . 92
Lumbar Adjustment . . . . . . . . . . . . . . 57 Front Seats . . . . . . . . . . . . . . . . . . . . . 57
M
MaintenanceRecords . . . . . . . . . . . . . . . . . . . . . . 457
Maintenance and Care Additional . . . . . . . . . . . . . . . . . . . . . 450
Maintenance Schedule . . . . . . . . . 442