2021 CHEVROLET SILVERADO 2500HD clock

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
202 Climate Controls
The fan, air delivery mode, air conditioning,
driver and passenger temperatures, and Sync
settings can be controlled by touching
CLIMATE on the infotainment Home Page or
the climate button in the climate control
display application tray. A selection can then
be made on the front climate control page
displayed.
Climate Control Status Display
The climate control status display appears
briefly when the center stack climate
controls are adjusted.Automatic Operation
The system automatically controls the fan
speed, air delivery, air conditioning, and
recirculation in order to heat or cool the
vehicle to the desired temperature.
When AUTO is lit, all four functions operate
automatically. Each function can also be
manually set and the selected setting is
displayed. Functions not manually set will
continue to be automatically controlled,
even if the AUTO indicator is not lit.
For automatic operation:
1. Press AUTO.
2. Set the temperature. Allow the system time to stabilize. Adjust the temperature
as needed for best comfort.
To improve fuel efficiency and to cool the
vehicle faster, recirculation may be
automatically selected in warm weather.
The recirculation light will not come on
when automatically controlled. See@
under “Manual Operation” for more details.
Manual Operation
9:Turn clockwise or counterclockwise to
increase or decrease the fan speed. Press the
knob to turn the fan off. When off is selected, a small amount of air may still
come out of the outlets depending on
vehicle speed. If any buttons are pressed or
knobs are turned, the climate control system
will turn on and operate at the current
setting.
Press AUTO to return to automatic
operation.
Driver and Passenger Temperature Control :
The temperature can be adjusted separately
for the driver and passenger.
Turn the knob clockwise or counterclockwise
to increase or decrease the driver or
passenger temperature setting. The driver
side or passenger side temperature display
shows the temperature setting increasing or
decreasing.
SYNC :
Press to link the passenger
temperature setting to the driver setting.
The SYNC indicator light will turn on. When
the passenger setting is adjusted, the SYNC
indicator light will turn off.
Air Delivery Mode Control : Press
z,Y,
or
[to change the direction of the
airflow. Any combination of the three
controls can be selected. An indicator light
comes on in the selected mode button.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
244 Driving and Operating
Hill Descent Control (HDC)
If equipped, Hill Descent Control (HDC) sets
and maintains vehicle speed while driving
down steep grades in a forward or reverse
gear. The HDC switch is on the center stack,
below the climate controls.
Press
5to enable or disable HDC. Vehicle
speed must be below 50 km/h (31 mph).
When enabled, the HDC light displays on
the instrument cluster.
A blinking HDC light indicates the system is
actively applying the brakes to maintain
vehicle speed. HDC can maintain vehicle
speeds between 1 and 22 km/h (1 and
14 mph) on grades greater than or equal
to 10%.
If HDC is to be used for more than
three minutes or on grades steeper than
25%, the transfer case should be put into
Four-Wheel Drive Low (4
n) to reduce the
possibility of brake overheating. Noise from the Electronic Brake Control
Module (EBCM) is normal when HDC is
active.
When HDC is activated, the initial HDC
speed is set to the current driving speed.
It can be increased or decreased by pressing
+RES or SET- on the steering wheel, or by
applying the accelerator or brake pedal. This
adjusted speed becomes the new set speed.
HDC will remain enabled between 30 and
60 km/h (19 and 37 mph); however, vehicle
speed cannot be set or maintained in this
range. HDC will automatically disable if the
vehicle speed is above 80 km/h (50 mph) or
above 60 km/h (37 mph) for at least
30 seconds.
5must be pressed again to re-enable HDC.
HDC may disable after an extended period
of use. If this happens, HDC will require
time to cool down. The length of time HDC
remains active depends on road conditions,
grade, set speed, vehicle loading, and
outside temperature.
When enabled, if the vehicle speed is above
30 km/h (19 mph) and below 60 km/h
(37 mph), a DIC message will display.
Driver Mode Control
Driver Mode Control (DMC) allows the driver
to adjust the overall driving experience to
better suit preference by adjusting multiple
systems to fit specific driving needs. Drive
mode availability and affected vehicle
subsystems are dependent upon vehicle trim
level, region, and optional features.
Mode Activation
To activate Tow/Haul Mode turn the knob
counterclockwise. To activate other drive
modes turn the knob clockwise.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
Driving and Operating 267
Warning (Continued)
.Read and follow all the instructions on
the fuel pump island.
.Turn off the engine when refueling.
.Keep sparks, flames, and smoking
materials away from fuel.
.Do not leave the fuel pump
unattended.
.Avoid using electronic devices while
refueling.
.Do not re-enter the vehicle while
pumping fuel.
.Keep children away from the fuel
pump and never let children
pump fuel.
.Before touching the fill nozzle, touch a
metallic object to discharge static
electricity from your body.
.Fuel can spray out if the fuel cap is
opened too quickly. This spray can
happen if the tank is nearly full, and is
more likely in hot weather. Open the
fuel cap slowly and wait for any hiss
noise to stop, then unscrew the cap all
the way.Turn the fuel cap counterclockwise to
remove. Fully insert and latch the fill nozzle,
begin fueling. For models with dual fuel
tanks, the fuel gauge shows an average of
both tanks. When refueling, refuel the
primary front tank first, then add fuel to the
auxiliary rear tank.
{Warning
Overfilling the fuel tank by more than
three clicks of a standard fill nozzle may
cause:
.Vehicle performance issues, including
engine stalling and damage to the fuel
system.
.Fuel spills.
.Under certain conditions, fuel fires.
Be careful not to spill fuel. Wait five seconds
after you have finished pumping before
removing the fill nozzle. Clean fuel from
painted surfaces as soon as possible. See
Exterior Care 0373. Reinstall the cap by
turning it clockwise until it clicks.
{Warning
If a fire starts while you are refueling, do
not remove the fill nozzle. Shut off the
flow of fuel by shutting off the pump or
by notifying the station attendant. Leave
the area immediately.
Caution
If a new fuel cap is needed, get the right
type of cap from your dealer. The wrong
type of fuel cap may not fit properly,
may turn on the malfunction indicator
lamp, and could damage the fuel system
and emissions system. See Malfunction
Indicator Lamp (Check Engine Light) 0111.
Filling a Portable Fuel Container
{Warning
Never fill a portable fuel container while
it is in the vehicle. Static electricity
discharge from the container can ignite
the fuel vapor. You or others could be
(Continued)

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
312 Vehicle Care
{Warning
Steam and scalding liquids from a hot
cooling system are under pressure.
Turning the pressure cap, even a little,
can cause them to come out at high
speed and you could be burned. Never
turn the cap when the cooling system,
including the pressure cap, is hot. Wait
for the cooling system and pressure cap
to cool.
Caution
Failure to follow the specific coolant fill
procedure could cause the engine to
overheat and could cause system
damage. If coolant is not visible in the
surge tank, contact your dealer.
If no coolant is visible in the surge tank, add
coolant.
1. Remove the coolant surge tank pressure cap when the cooling system, including
the coolant surge tank pressure cap and
upper radiator hose, is no longer hot.
Turn the pressure cap slowly
counterclockwise about one full turn. If a
hiss is heard, wait for that to stop.
A hiss means there is still some
pressure left.
2. Keep turning the pressure cap slowly, and remove it.
3. Fill the coolant surge tank with the proper mixture to the full cold mark.
4. With the coolant surge tank pressure cap off, start the engine and let it run until
the engine coolant temperature gauge
indicates approximately 90 °C (195 °F).
By this time, the coolant level inside the
coolant surge tank may be lower. If the
level is lower, add more of the proper
mixture to the coolant surge tank until
the level reaches the indicated mark.
5. Replace the pressure cap tightly.
6. Verify coolant level after the engine is shut off and the coolant is cold.
If necessary, repeat coolant fill procedure
Steps 1–6.Caution
If the pressure cap is not tightly installed,
coolant loss and engine damage may
occur. Be sure the cap is properly and
tightly secured.
Engine Overheating
If the vehicle has the Duramax diesel
engine, see the Duramax diesel supplement.
Caution
Do not run the engine if there is a leak
in the engine cooling system. This can
cause a loss of all coolant and can
damage the system and vehicle. Have
any leaks fixed right away.
The vehicle has several indicators to warn of
engine overheating.
There is a coolant temperature gauge in the
vehicle's instrument cluster. See Engine
Coolant Temperature Gauge 0108.
In addition, there are ENGINE OVERHEATED
STOP ENGINE, ENGINE OVERHEATED IDLE
ENGINE, and ENGINE POWER IS REDUCED
messages in the Driver Information
Center (DIC).

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
Vehicle Care 325
Halogen Bulbs
{Warning
Halogen 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
Base Level Headlamp Assembly
1. Sidemarker lamp
2. Low-Beam Headlamp
3. High-Beam Headlamp
4. Turn Signal/Park Lamps
Midlevel Headlamp Assembly
1. Turn Signal Lamps
Headlamp Replacement
Base Level1. Open the hood.
2. Remove the headlamp bulb cover.
3. Turn the bulb socket counterclockwise to remove it from the headlamp assembly.
4. Unplug the electrical connector from the bulb by releasing the clip on the
connector.
5. Replace the bulb and reverse Steps 1–4 to reinstall.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
326 Vehicle Care
Midlevel and Uplevel
See your dealer for headlamp replacement.
Uplevel
See your dealer for turn signal replacement.
Turn Signal Lamp Replacement
1. Open the hood.
2. Turn the bulb socket counterclockwise toremove it from the headlamp assembly
and pull it straight out.
3. Remove the bulb by pulling it straight out of the bulb socket.
4. Replace the bulb and reverse Steps 1–3 to reinstall.
Taillamps, Turn Signal, Stoplamps,
and Back-Up Lamps
Base Level Taillamp Assembly
1. Stoplamp/Taillamp/Turn Signal Lamp
2. Back-Up Lamp
3. Side Marker Lamp
Uplevel Taillamp Assembly
1500 shown 2500/3500 similar
1. Back-Up Lamp
It is recommended to replace the grommets
when replacing a bulb. See your dealer.
To replace one of these bulbs:
1. Open the tailgate.

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
Vehicle Care 327
2. Remove the two rear lamp assemblyscrews.
3. Pull the rear lamp assembly outward and rearward away from the box side to
remove it from the vehicle.4. Turn the bulb socket counterclockwise.
5. Pull the bulb straight out from thesocket.
6. Replace the bulb and reverse Steps 1–5 to reinstall.
Center High-Mounted Stoplamp
(CHMSL) and Cargo Lamp
This procedure is for the regular cab only.
For crew cab and double cab see your
dealer.
1. Cargo Lamp Bulbs
2. Center High-Mounted Stoplamp (CHMSL) Bulb

Chevrolet Silverado 2500 HD/3500 HD Owner Manual (GMNA-Localizing-U.
S./Canada/Mexico-14632154) - 2021 - CRC - 11/20/20
328 Vehicle Care
To replace one of these bulbs:
1. Remove the two screws and lift off thelamp assembly.
2. Turn the bulb socket counterclockwise and pull it straight out.
3. Pull the bulb straight out from the socket.
License Plate Lamp
To replace the bulb:
1. Reach behind the rear bumper and locate the bulb.
2. Turn the bulb socket counterclockwise and pull the bulb straight out of the
socket.
3. Replace the bulb and reverse Step 2 toreinstall.
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 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.
Headlamp Wiring
An electrical overload may cause the lamps
to go on and off, or in some cases to
remain off. Have the headlamp wiring
checked right away if the lamps go on and
off or remain off.
Windshield Wipers
If the wiper motor overheats due to heavy
snow or ice, the windshield wipers will stop
until the motor cools and will then restart.
Although the circuit is protected from
electrical overload, overload due to heavy
snow or ice may cause wiper linkage
damage. Always clear ice and heavy snow
from the windshield before using the
windshield wipers.
If the overload is caused by an electrical
problem and not snow or ice, be sure to get
it fixed.