warning CHEVROLET SILVERADO 2500HD 2021 Repair Manual

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
Instruments and Controls 111
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 allowed to inflate.
If the word OFF or the off symbol is lit on
the passenger 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 avoid injury to yourself
or others, have the vehicle serviced right
away. SeeAirbag Readiness Light 0110
for more information, including important
safety information.
Charging System Light
The charging system light comes on briefly
when the ignition is turned on, but the
engine is not running, as a check to show
the light is working. It should go out when
the engine is started.
If the light stays on, or comes on while
driving, there may be a problem with the
electrical charging system. Have it checked
by your dealer. Driving while this light is on
could drain the battery.
When this light comes on, or is flashing, the
Driver Information Center (DIC) also displays
a message.
If a short distance must be driven with the
light on, be sure to turn off all accessories,
such as the radio and air conditioner. Find a
safe place to stop the vehicle.
Malfunction Indicator Lamp
(Check Engine Light)
This light is part of the vehicle’s emission
control on-board diagnostic system. If this
light is on while the engine is running, a
malfunction has been detected and the
vehicle may require service. The light should
come on to show that it is working when
the ignition is on and the engine is not
running. See Ignition Positions (Keyless
Access) 0226 or
Ignition Positions (Key Access) 0224.
Malfunctions are often indicated by the
system before any problem is noticeable.
Being aware of the light and seeking service
promptly when it comes on may prevent
damage.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
Instruments and Controls 113
operation. SeeAdd-On Electrical Equipment
0 297. See your dealer if assistance is
needed.
The vehicle may not pass inspection if:
.The light is on when the engine is
running.
.The light does not come on when the
ignition is on while the engine is off.
.Critical emission control systems have not
been completely diagnosed. If this
happens, the vehicle would not be ready
for inspection and might require
several days of routine driving before the
system is ready for inspection. This can
happen if the 12-volt battery has recently
been replaced or run down, or if the
vehicle has been recently serviced.
See your dealer if the vehicle will not pass
or cannot be made ready for the test.
Brake System Warning Light
MetricEnglish This light should come on briefly when the
vehicle is turned on. If it does not come on
then, have it fixed so it will be ready to
warn you if there is a problem.
If the light comes on and stays on at start
up, there is a brake problem. Have the brake
system inspected right away.
If the light comes on while driving, pull off
the road and stop carefully. If equipped with
electric brake boost, vehicle speed may be
limited when the brake system warning
light comes on. The brake pedal might be
harder to push, or the brake pedal may go
closer to the floor. It could take longer to
stop. If the light is still on, have the vehicle
towed for service. See
Towing the Vehicle
0 369.
{Warning
The brake system might not be working
properly if the brake system warning
light is on. Driving with the brake system
warning light on can lead to a crash.
If the light is still on after the vehicle has
been pulled off the road and carefully
stopped, have the vehicle towed for
service.
Electric Parking Brake Light
MetricEnglish
This light comes on when the parking brake
is applied. If the light continues flashing
after the parking brake is released, or while
driving, there is a problem with the Electric
Parking Brake system. A message may also
display in the Driver Information
Center (DIC).
If the light does not come on, or remains
flashing, see your dealer.
Service Electric Parking Brake
Light

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
114 Instruments and Controls
This light should come on briefly when
starting the vehicle. If it does not come on,
have it fixed so it will be ready to warn if
there is a problem.
If this light stays on, take the vehicle to
your dealer as soon as possible. See the
information for the Electric Parking Brake
underElectric Parking Brake 0240.
A message may also display in the Driver
Information Center (DIC).
Antilock Brake System (ABS)
Warning Light
This warning light should come on briefly
when the vehicle is turned on. If the light
does not come on, have it fixed so it will be
ready to warn if there is a problem.
If the light comes on while driving, safely
stop as soon as it is possible and turn off
the vehicle. Then turn on the vehicle again
to reset the system. If the ABS warning light stays on, or comes
on again while driving, the vehicle needs
service. A chime may also sound when the
light stays on.
If the ABS warning light is the only light on,
the vehicle has regular brakes, but ABS is
not functioning.
If both the ABS warning light and the brake
system warning light are on, ABS is not
functioning and there is a problem with the
regular brakes. See your dealer for service.
See
Brake System Warning Light 0113.
Four-Wheel-Drive Light
Auto Mode Shown, Other Modes Similar
If equipped, the four-wheel-drive light
displays what mode the vehicle is in. The
light will show each mode: 2WD, 4HI, AUTO
(all transfer cases); 4LOW and N (two-speed
transfer case only). The light will flash when a shift is in
progress. Once the shift is complete the
light will be steady.
If the light turns amber, there may be a
malfunction with the four-wheel-drive
system. See your dealer.
See
Four-Wheel Drive 0236.
Tow/Haul Mode Light
For vehicles with the Tow/Haul Mode
feature, this light comes on when the Tow/
Haul Mode has been activated.
See Tow/Haul Mode 0235.
Hill Descent Control Light

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
Instruments and Controls 115
If equipped, the Hill Descent Control light
comes on when the system is ready for use.
When the light flashes, the system is active.
SeeHill Descent Control (HDC) 0244.
Lane Departure Warning (LDW)
Light
This light is green if LDW is on and ready to
operate.
This light changes to amber and flashes to
indicate that the lane marking has been
crossed without using a turn signal in that
direction.
See Lane Departure Warning (LDW) 0262.
Vehicle Ahead Indicator
If equipped, this indicator will display green
when a vehicle is detected ahead and amber
when you are following a vehicle ahead
much too closely.
See Forward Collision Alert (FCA) System
0 257.
Traction Off Light
This light comes on briefly when the vehicle
is turned on. If it does not, have the vehicle
serviced by your dealer. If the system is
working normally, the indicator light then
turns off. The traction off light comes on when the
Traction Control System (TCS) has been
turned off. If Electronic Stability Control
(ESC) is turned off, TCS is also turned off. To
turn TCS and ESC off and on, see
Traction
Control/Electronic Stability Control 0242.
If TCS is off, wheel spin is not limited unless
necessary to help protect the driveline from
damage. Adjust driving accordingly.
Traction Control System (TCS)/
Electronic Stability Control Light
This light comes on briefly when the vehicle
is turned on.
If the light does not come on, have the
vehicle serviced by your dealer. If the
system is working normally, the indicator
light turns off.
If the light is on and not flashing, the TCS
and potentially the ESC system are not fully
operational and may not assist in
maintaining control. Adjust driving

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
116 Instruments and Controls
accordingly. If the condition persists, see
your dealer as soon as possible. A Driver
Information Center (DIC) message may
display.
The light flashes when the TCS and/or the
ESC system is actively working.
SeeTraction Control/Electronic Stability
Control 0242.
Trailer Sway Control Light (Uplevel
Cluster)
This light will flash when Trailer Sway
Control is active. See Trailer Sway Control
(TSC) 0285.
Electronic Stability Control (ESC)
Off Light
This light comes on briefly when the vehicle
is turned on. If the light does not come on,
have the vehicle serviced by your dealer.
If the system is working normally, the
indicator light then turns off.
serviced by your dealer. If the system is
working normally, the indicator light then
turns off. This light comes on when the
Electronic Stability Control (ESC) system is
turned off. If ESC is off, the Traction Control
System (TCS) is also off. To turn ESC off and
on, see Traction Control/Electronic Stability
Control 0242.
If ESC and TCS are off, the systems do not
assist in controlling the vehicle. Adjust
driving accordingly.
Engine Coolant Temperature
Warning Light
This light comes on briefly while starting
the vehicle.
If it does not, have the vehicle serviced by
your dealer. If the system is working
normally the indicator light goes off.
Caution
The engine coolant temperature warning
light indicates that the vehicle has
overheated. Driving with this light on can
damage the engine and it may not be
covered by the vehicle warranty. See
Engine Overheating 0312.
The engine coolant temperature warning
light comes on when the engine has
overheated.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
118 Instruments and Controls
If the light comes on and stays on, it means
that oil is not flowing through the engine
properly. The vehicle could be low on oil
and might have some other system
problem. See your dealer.
Low Fuel Warning Light
This light is near the fuel gauge and comes
on briefly when the ignition is turned on as
a check to show it is working.
It also comes on when the fuel tank is low
on fuel. The light turns off when fuel is
added. If it does not, have the vehicle
serviced.
Security Light
The security light should come on briefly as
the engine is started. If it does not come on,
have the vehicle serviced by your dealer.
If the system is working normally, the
indicator light turns off.
If the light stays on and the engine does
not start, there could be a problem with the
theft-deterrent system. SeeImmobilizer
Operation 029.
High-Beam On Light
This light comes on when the high-beam
headlamps are in use. See Headlamp High/
Low-Beam Changer 0136.
IntelliBeam Light
This light comes on when the IntelliBeam
system, if equipped, is enabled. See Exterior
Lamp Controls 0134.
Front Fog Lamp Light
For vehicles with fog lamps, this light comes
on when the fog lamps are on.
The light goes out when the fog lamps are
turned off. See Fog Lamps0138.
Lamps On Reminder
This light comes on when the exterior lamps
are in use, except when only the Daytime
Running Lamps (DRL) are active. See Exterior
Lamp Controls 0134.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
Instruments and Controls 123
Driver Assistance :If equipped, shows
information for Lane Departure Warning
(LDW) and Forward Collision Alert (FCA).
Info Page Options : Scroll to choose which
info pages appear on the DIC. Press the
thumbwheel to select or deselect.
Blank Page : Shows no information.
Head-Up Display (HUD)
{Warning
If the HUD image is too bright or too
high in your field of view, it may take
you more time to see things you need to
see when it is dark outside. Be sure to
keep the HUD image dim and placed low
in your field of view.
If equipped with HUD, some information
about the operation of the vehicle is
projected onto the windshield. The image is
projected through the HUD lens on top of
the instrument panel. The information
appears as an image focused out toward the
front of the vehicle.
Caution
If you try to use the HUD image as a
parking aid, you may misjudge the
distance and damage your vehicle. Do not
use the HUD image as a parking aid.
The HUD information can be displayed in
various languages. The speedometer reading
and other numerical values can be displayed
in either English or metric units.
The language selection is changed through
the radio, and the units of measurement is
changed through the instrument cluster. See
Settings 0181 and “Options” under
Instrument Cluster 0102.
HUD Display on the Windshield Depending on how the vehicle is equipped,
the HUD may display some of the following
vehicle information and vehicle messages or
alerts:
.Speed
.Audio
.Phone
.Navigation
.Driver Assistance Features
.Vehicle Messages
Some vehicle messages or alerts displayed in
the HUD may be cleared by using the
steering wheel controls.
The HUD control is to the left of the
steering wheel.
To adjust the HUD image: 1. Adjust the driver seat.
2. Start the engine.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
Instruments and Controls 125
English Shown, Metric Similar
Navigation/Active OnStar View : This
displays the speed view along with
indicators for vehicle ahead, Lane Departure
Warning/Lane Keep Assist, trailer sway, and
pedestrian advisory. Turn-by-Turn navigation
information is shown during active route.
The compass heading is displayed when
navigation routing is not active.
Navigation Turn-by-Turn Alerts shown in the
instrument cluster may also be displayed in
any HUD view.English Shown, Metric Similar
Off Road View : This displays the speed
view along with indicators for vehicle ahead,
Lane Departure Warning/Lane Keep Assist,
trailer sway, four-wheel drive status, and
pedestrian advisory. Off-road information
such as pitch angle, steering angle, and
rolling angle is also shown.
Care of the HUD
Clean the inside of the windshield to remove
any dirt or film that could reduce the
sharpness or clarity of the HUD image.
Clean the HUD lens with a soft cloth
sprayed with glass cleaner. Wipe the lens
gently, then dry it.
HUD Troubleshooting
Check that:
.Nothing is covering the HUD lens.
.The HUD brightness setting is not too
dim or too bright.
.The HUD is adjusted to the proper height.
.Polarized sunglasses are not worn.
.The windshield and HUD lens are clean.
If the HUD image is not correct, contact
your dealer.
The windshield is part of the HUD system.
See Windshield Replacement 0323.
Vehicle Messages
Messages displayed on the Driver
Information Center (DIC) indicate the status
of the vehicle or some action that may be
needed to correct a condition. Multiple
messages may appear one after another.
The messages that do not require
immediate action can be acknowledged and
cleared by pressing the thumbwheel. The
messages that require immediate action
cannot be cleared until that action is
performed.
All messages should be taken seriously;
clearing the message does not correct the
problem.
If a SERVICE message appears, see your
dealer.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
134 Lighting
Lighting
Exterior Lighting
Exterior Lamp Controls . . . . . . . . . . . . . . . . 134
Exterior Lamps Off Reminder . . . . . . . . . . 136
Headlamp High/Low-Beam Changer . . . 136
Flash-to-Pass . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
Daytime Running Lamps (DRL) . . . . . . . . . 136
Automatic Headlamp System . . . . . . . . . . 136
Hazard Warning Flashers . . . . . . . . . . . . . . 137
Turn and Lane-Change Signals . . . . . . . . . 138
Fog Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
Task Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Auxiliary Roof-Mounted Lamp . . . . . . . . . 139
Exterior Cargo Lamps . . . . . . . . . . . . . . . . . . 139
Interior Lighting
Instrument Panel IlluminationControl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Dome Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Reading Lamps . . . . . . . . . . . . . . . . . . . . . . . . . 141
Lighting Features
Entry Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Exit Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Battery Load Management . . . . . . . . . . . . . 141
Battery Power Protection . . . . . . . . . . . . . . 142
Exterior Lighting Battery Saver . . . . . . . . 142
Exterior Lighting
Exterior Lamp Controls
The exterior lamp control is on the
instrument panel to the left of the steering
wheel.
O: Turns off the automatic headlamps and
Daytime Running Lamps (DRL). Turn the
headlamp control to
Oagain to turn the
automatic headlamps or DRL back on.
For vehicles first sold in Canada, off will only
work when the vehicle is in P (Park). AUTO :
Automatically turns on the
headlamps, parking lamps, taillamps,
instrument panel lights, roof marker lamps
(if equipped), front/rear sidemarker lamps,
and license plate lamps.
;: Turns on the parking lamps including
all lamps, except the headlamps and fog
lamps, if equipped.
For some trim levels and series of trucks
first sold in Canada, the headlamps may
turn on with the parking lamps.
2: Turns on the headlamps together with
the parking lamps, taillamps, instrument
panel lights, roof marker lamps (if
equipped), front/rear sidemarker lamps,
and license plate lamps.
When the headlamps are turned on while
the vehicle is on, the headlamps turn off
automatically 10 minutes after the ignition
is turned off. When the headlamps are
turned on while the vehicle is off, the
headlamps will stay on for 10 minutes
before turning off to prevent the battery
from being drained. Turn the headlamp
control off and then back to the headlamp
on position to make the headlamps stay on

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
Lighting 137
There is a light sensor on top of the
instrument panel. Do not cover the sensor,
otherwise the headlamps will come on when
they are not needed.
The system may also turn on the headlamps
when driving through a parking garage or
tunnel.
If the vehicle is started in a dark garage, the
automatic headlamp system comes on
immediately. If it is light outside when the
vehicle leaves the garage, there is a slight
delay before the automatic headlamp
system changes to the Daytime Running
Lamps (DRL). During that delay, the
instrument cluster may not be as bright as
usual. Make sure the instrument panelillumination control is in the full bright
position. See
Instrument Panel Illumination
Control 0140.
When it is bright enough outside, the
headlamps will turn off or may change
to DRL.
The automatic headlamp system turns off
when the exterior lamp control is turned to
Oor the ignition is off.
Lights On with Wipers
If the windshield wipers are activated in
daylight with the engine on, and the
exterior lamp control is in AUTO, the
headlamps, parking lamps, and other
exterior lamps come on. The transition time
for the lamps coming on varies based on
wiper speed. When the wipers are not
operating, these lamps turn off. Move the
exterior lamp control to
Oor;to disable
this feature.
Hazard Warning Flashers
|: Press this button to make the front
and rear turn signal lamps flash on and off.
Press again to turn the flashers off.
When the hazard warning flashers are on,
the vehicle's turn signals will not work.