
Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
OnStar 413
.Receive a Diagnostic check of the vehicle's
key operating systems.
.Receive Roadside Assistance.
.Manage Wi-Fi Settings, if equipped.
Press
>to get a priority connection to an
OnStar Advisor available 24/7 to:
.Get help for an emergency.
.Be a Good Samaritan or respond to an
AMBER Alert.
.Get assistance in severe weather or other
crisis situations and find evacuation
routes.
OnStar Services
Emergency
Emergency Services require an active safety
and security plan. With Automatic Crash
Response, built-in sensors can automatically
alert a specially trained OnStar Advisor who
is immediately connected in to the vehicle
to help.
Press
>for a priority connection to an
OnStar Advisor who can contact emergency
service providers, direct them to your exact
location, and relay important information. With OnStar Crisis Assist, specially trained
Advisors are available 24 hours a day, 7 days
a week, to provide a central point of
contact, assistance, and information during a
crisis.
With Roadside Assistance, Advisors can
locate a nearby service provider to help with
a flat tire, a battery jump, or an empty
gas tank.
Security
If equipped, OnStar provides these services:
.With Stolen Vehicle Assistance, OnStar
Advisors can use GPS to pinpoint the
vehicle and help authorities quickly
recover it.
.With Remote Ignition Block, if equipped,
OnStar can block the engine from being
restarted.
.With Stolen Vehicle Slowdown,
if equipped, OnStar can work with law
enforcement to gradually slow the
vehicle down.
Theft Alarm Notification
If equipped, if the doors are locked and the
vehicle alarm sounds, a notification by text,
e-mail, or phone call will be sent. If the
vehicle is stolen, an OnStar Advisor can work
with authorities to recover the vehicle.
OnStar Additional
Information
In-Vehicle Audio Messages
Audio messages may play important
information at the following times:
.Prior to vehicle purchase. PressQto
set up an account.
.After change in ownership and at
90 days.
Transferring Service
PressQto request account transfer
eligibility information. The Advisor can
cancel or change account information.
Selling/Transferring the Vehicle
Call 1-888-4ONSTAR (1-888-466-7827)
immediately to terminate your OnStar or
connected services if the vehicle is disposed
of, sold, transferred, or if the lease ends.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
420 Index
IndexA
Accessories and Modifications . . . . . . . . . . . 302
Accessory Power . . . . . . . . . . . . . . . . . . . . . . . . . 229
Add-On Electrical Equipment . . . . . . . . . . . . . 297
Adding a Snow Plow or SimilarEquipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297
Additional Information OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413
Additional Maintenance and Care . . . . . . . . 390
Adjustments Lumbar, Front Seats . . . . . . . . . . . . . . . . . . . . 45
Agreements Trademarks and License . . . . . . . . . . . . . . . 190
Air Cleaner/Filter, Engine . . . . . . . . . . . . . . . . 309
Air Conditioning . . . . . . . . . . . . . . . . . . . . .199, 201
Air Filter
Life System . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
Air Filter, Passenger Compartment . . . . . . . 204
Air Vents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Airbag System Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
How Does an Airbag Restrain? . . . . . . . . . . 61
Passenger Sensing System . . . . . . . . . . . . . . 62
What Makes an Airbag Inflate? . . . . . . . . . 61
What Will You See after an AirbagInflates? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
When Should an Airbag Inflate? . . . . . . . . 60
Where Are the Airbags? . . . . . . . . . . . . . . . . 59 Airbags
Adding Equipment to the Vehicle . . . . . . . 66
Passenger Status Indicator . . . . . . . . . . . . . 110
Readiness Light . . . . . . . . . . . . . . . . . . . . . . . . 110
Servicing Airbag-Equipped Vehicles . . . . . . 66
System Check . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Alarm
Vehicle Security . . . . . . . . . . . . . . . . . . . . . . . . 27
Alert Lane Change . . . . . . . . . . . . . . . . . . . . . . . . . . . 261
Side Blind Zone (SBZA) . . . . . . . . . . . . . . . . . 260
All-Season Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 337
All-Terrain Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 337
AM-FM Radio . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
Antenna Fixed Mast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
Multi-band . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
Antilock Brake System (ABS) . . . . . . . . . . . . . 240 Warning Light . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Appearance Care Exterior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373
Interior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378
Apple CarPlay and Android Auto . . . . . . . . . 180
Assistance Program, Roadside . . . . . . . . . . . . 404
Assistance Systems for Driving . . . . . . . . . . 257
Assistance Systems for Parking and Backing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
Index 429
Seats (cont'd)Rear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Reclining Seatbacks . . . . . . . . . . . . . . . . . . . . . 45
Underseat Storage . . . . . . . . . . . . . . . . . . . . . . 92
Securing Child Restraints . . . . . . . . . . . . . . 84, 87
Security Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413
Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Vehicle Alarm . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205 Accessories and Modifications . . . . . . . . . 302
Climate Control System . . . . . . . . . . . . . . . . 199
Doing Your Own Work . . . . . . . . . . . . . . . . . 302
Maintenance Records . . . . . . . . . . . . . . . . . . 396
Maintenance, General Information . . . . . 383
Parts Identification . . . . . . . . . . . . . . . . . . . . . 397
Scheduling Appointments . . . . . . . . . . . . . . 405
Service Electric Parking Brake Light . . . . . . . 113
Services Special Application . . . . . . . . . . . . . . . . . . . . . 390
Servicing System . . . . . . . . . . . . . . . . . . . . . . . . 170
Servicing the Airbag . . . . . . . . . . . . . . . . . . . . . . 66
Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
Shift Lock Control Function Check, Automatic Transmission . . . . . . . . . . . . . . . . 322
Shifting Into Park . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230 Shifting (cont'd)
Out of Park . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
Side Blind Zone Alert (SBZA) . . . . . . . . . . . . . 260
Signals, Turn and Lane-Change . . . . . . . . . . . .138
Snow Plow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297
Software Updates . . . . . . . . . . . . . . . . . . . . . . . . 150
Special Application Services . . . . . . . . . . . . . . 390
Specifications and Capacities . . . . . . . . . . . . . 398
Speedometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Start Assist, Hill . . . . . . . . . . . . . . . . . . . . . . . . . . 242
Start Vehicle, Remote . . . . . . . . . . . . . . . . . . . . . 20
Starter Switch Check . . . . . . . . . . . . . . . . . . . . . . 321
Starting the Engine . . . . . . . . . . . . . . . . . . . . . . 227
Steering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 Fluid, Power . . . . . . . . . . . . . . . . . . . . . . . . . . . 314
Heated Wheel . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Wheel Adjustment . . . . . . . . . . . . . . . . . . . . . . 96
Wheel Controls . . . . . . . . . . . . . . . . . . . . . . . . . 96
Steering Column Lock . . . . . . . . . . . . . . . . . . . . . 28
Steering Wheel Controls . . . . . . . . . . . . . . . . . 146
Steps Power Assist . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Stoplamps and Back-up Lamps Bulb Replacement . . . . . . . . . . . . . . . . . . . . . . 326
Storage Rear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Storage Areas Center Console . . . . . . . . . . . . . . . . . . . . . . . . . 92 Storage Areas (cont'd)
Floor Console . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Glove Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Underseat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Storage Compartments . . . . . . . . . . . . . . . . . . . .91
Struts Gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
Stuck Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
Sun Visors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Sunroof . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 Navigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
System Brake Pad Life . . . . . . . . . . . . . . . . . . . . . . . . . 316
Engine Air Filter Life . . . . . . . . . . . . . . . . . . . 308
Forward Collision Alert (FCA) . . . . . . . . . . . 257
Global Positioning . . . . . . . . . . . . . . . . . . . . . 168
Infotainment . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411
Noise Control . . . . . . . . . . . . . . . . . . . . . . . . . . 320
OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
Systems
Driver Assistance . . . . . . . . . . . . . . . . . . . . . . 247
T
Tachometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Tailgate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
430 Index
TaillampsBulb Replacement . . . . . . . . . . . . . . . . . . . . . . 326
Task Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Teen Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .187
Text Telephone (TTY) Users . . . . . . . . . . . . . . 403
Theft-Deterrent Systems . . . . . . . . . . . . . . . . . . 29 Immobilizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336 All-Season . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337
All-Terrain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337
Buying New Tires . . . . . . . . . . . . . . . . . . . . . . 351
Chains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354
Changing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356
Designations . . . . . . . . . . . . . . . . . . . . . . . . . . . 339
Different Size . . . . . . . . . . . . . . . . . . . . . . . . . . 352
Full-Size Spare . . . . . . . . . . . . . . . . . . . . . . . . . 366
If a Tire Goes Flat . . . . . . . . . . . . . . . . . . . . . 355
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348
Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341
Pressure Light . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Pressure Monitor Operation . . . . . . . . . . . 343
Pressure Monitor System . . . . . . . . . . . . . . 342
Rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348
Sidewall Labeling . . . . . . . . . . . . . . . . . . . . . . 338
Terminology and Definitions . . . . . . . . . . . 339
Uniform Tire Quality Grading . . . . . . . . . . 352
Wheel Alignment and Tire Balance . . . . 354 Tires (cont'd)
Wheel Replacement . . . . . . . . . . . . . . . . . . . . 354
When It Is Time for New Tires . . . . . . . . . 350
Winter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337
Top Tier Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
Tow/Haul Mode . . . . . . . . . . . . . . . . . . . . . . . . . 235
Tow/Haul Mode Light . . . . . . . . . . . . . . . . . . . . 114
Towing Driving Characteristics . . . . . . . . . . . . . . . . . 268
Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276
General Information . . . . . . . . . . . . . . . . . . . 268
Recreational Vehicle . . . . . . . . . . . . . . . . . . . 370
Trailer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272
Trailer Sway Control (TSC) . . . . . . . . . . . . . 285
Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369
Traction
Limited-Slip Differential . . . . . . . . . . . . . . . . 245
Off Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
Traction Control/Electronic Stability Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
Trademarks and License Agreements . . . . . 190
Trailer
Sway Control (TSC) . . . . . . . . . . . . . . . . . . . . 285
Tow Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Towing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272
Trailer Towing
App . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286
Trailering App . . . . . . . . . . . . . . . . . . . . . . . . . . . 286 Transfer Case . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
Transmission
Automatic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
Fluid, Automatic . . . . . . . . . . . . . . . . . . . . . . . 308
Transportation Program, Courtesy . . . . . . . 406
Trip Odometer . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Truck Bed Camera Rearview Mirror . . . . . . . .37
Truck-Camper Loading Information . . . . . . . 222
Turn and Lane-Change Signals . . . . . . . . . . . .138
Turn Signal Bulb Replacement . . . . . . . . . . . . . . . . . . . . . . 326
U
Underseat Storage . . . . . . . . . . . . . . . . . . . . . . . . 92
Uniform Tire Quality Grading . . . . . . . . . . . . 352
Universal Remote System . . . . . . . . . . . . . . . . . 131Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Updates Map Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
USB Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
Using the Navigation System . . . . . . . . . . . . .158
Using the System . . . . . . . . . . . . . . . . . . . . . . . . .147
Using This Manual . . . . . . . . . . . . . . . . . . . . . . . . . .2
V
Vehicle Alarm System . . . . . . . . . . . . . . . . . . . . . . . . . . 27