2023 GMC SIERRA clock

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Driving and Operating 243
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.
Modes:
Normal Mode : Use for normal city and
highway driving to provide a smooth ride.
This setting provides balance between
comfort and handling. This is the standard/
default mode. There is no persistent
indicator in the instrument cluster for
this mode.
6Snow/Ice Mode : Snow/Ice Mode
improves vehicle acceleration on snow and
ice covered roads. When active, Snow/Ice
Mode will adjust acceleration to optimize
traction on slippery surfaces. This can
compromise the acceleration on dry asphalt.
This feature is not intended for use when
the vehicle is stuck in sand, mud, ice, snow,
or gravel. If the vehicle becomes stuck, see If
the Vehicle Is Stuck 0214.
7Off-Road Mode : Use this mode for
off-road recreational driving. Off-Road Mode
should be used to improve driving at
moderate speeds, on grass, gravel, dirt,
unpaved roads, or snow-covered roads. The
accelerator pedal is tuned for off-road use.
This mode modifies pedal mapping,
transmission shift pattern, Antilock Brake

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Driving and Operating 267
{Warning
Fuel vapors and fuel fires burn violently
and can cause injury or death.
Follow these guidelines to help avoid
injuries to you and others:
.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.(Continued)
Warning (Continued)
.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
0374. 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)
0 120.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/18/22
Vehicle Care 313
{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 0117.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/18/22
Vehicle Care 325
Liftgate
Headlamp Aiming
Front Headlamp Aiming
Headlamp aim has been preset and should
need no further adjustment.
If the vehicle is damaged in a crash, the
headlamp aim may be affected.
If adjustment to the headlamps is necessary,
see your dealer.
Bulb Replacement
For the proper type of replacement bulbs,
or any bulb changing procedure not listed in
this section, contact your dealer.
Caution
Do not replace incandescent bulbs with
aftermarket LED replacement bulbs. This
can cause damage to the vehicle electrical
system.
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. Turn Signal Lamps
Headlamp Replacement
See your dealer for headlamp replacement.
Turn Signal Lamp Replacement
Base Level1. Open the hood.
2. Turn the bulb socket counterclockwise to remove it from the headlamp assembly
and pull it straight out.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/18/22
326 Vehicle Care
3. Remove the bulb by pulling it straightout of the bulb socket.
4. Replace the bulb and reverse Steps 1–3 to reinstall.
Uplevel
See your dealer for headlamp replacement.
Taillamps, Turn Signal, Stoplamps,
and Back-Up Lamps
Base Level Taillamp Assembly
1. Stoplamp/Turn Signal Lamp
2. Back-Up Lamp
Uplevel Taillamp Assembly
See your dealer for taillamp replacement.
It is recommended to replace the grommets
when replacing a bulb. See your dealer.
To replace one of these bulbs: 1. Open the tailgate.
2. Remove the two rear lamp assembly screws.
4. Pull the rear lamp assembly outward andrearward away from the box side to
remove it from the vehicle.
5. Turn the bulb socket counterclockwise.
6. Pull the bulb straight out from the socket.
7. Replace the bulb and reverse Steps 1–5 to reinstall.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/18/22
Vehicle Care 327
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
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 and circuit breakers to
protect against an electrical system
overload.
When the current electrical load is too
heavy, the circuit breaker opens and closes,
protecting the circuit until the current load
returns to normal or the problem is fixed.
This greatly reduces the chance of circuit
overload and fire caused by electrical
problems.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/18/22
Vehicle Care 357
Warning (Continued)
4. Turn off the engine and do notrestart while the vehicle is raised.
5. Do not allow passengers to remain in the vehicle.
6. Place wheel blocks, if equipped, on both sides of the tire at the opposite
corner of the tire being changed.
When the vehicle has a flat tire (2), use the
following example as a guide to assist in the
placement of the wheel blocks (1),
if equipped.
1. Wheel Block (If Equipped)
2. Flat Tire
The following information explains how to
use the jack and change a tire.
Tire Changing
Removing the Spare Tire and Tools
1. Jack
2. Jack Knob
3. Tool Kit
4. Wing Nut Retaining Tool Kit
5. Wheel Blocks
6. Wing Nut Retaining Wheel Blocks
The equipment is under the second row
seats, if equipped, or behind the front row
seats on regular cab models. 1. Turn the knob on the jack counterclockwise to lower the jack head
to release the jack from its holder. 2. Turn the wing nut counterclockwise to
remove the wheel blocks and the wheel
block retainer.
3. Turn the wing nut used to retain the storage bag and tools counterclockwise
to remove it.
Use the jack handle extensions and the
wheel wrench to remove the
underbody-mounted spare tire.1. Spare Tire (Valve Stem Pointed Down)
2. Tire/Wheel Retainer
3. Hoist Cable
4. Hoist Assembly
5. Hoist Shaft
6. Jack Handle Extensions

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/18/22
358 Vehicle Care
7. Wheel Wrench
8. Spare Tire Lock (If Equipped)
9. Hoist Shaft Access Hole
10. Hoist End of Extension Tool
1. Open the spare tire lock cover on thebumper and use the ignition key to
remove the spare tire lock (8). To remove
the spare tire lock, insert the ignition
key, turn, and pull straight out.
2. Assemble the wheel wrench (7) and thetwo jack handle extensions (6), as shown.
Spare Tire Cable (If Equipped)
3. If the vehicle is equipped with a spare tire cable disconnect the cable from the
attachment on the frame by unclipping
it from the frame attachment bracket.
4. Insert the hoist end (open end) (10) ofthe extension through the hole (9) in the
rear bumper.
Do not use the chiseled end of the wheel
wrench.
Be sure the hoist end of the
extension (10) connects to the hoist
shaft. The ribbed square end of the
extension is used to lower the spare tire.
5. Turn the wheel wrench counterclockwise to lower the spare tire to the ground.
Continue to turn the wheel wrench until
the spare tire can be pulled out from
under the vehicle.
6. Pull the spare tire out from under the vehicle.
7. Tilt the tire toward the vehicle withsome slack in the cable to access the
tire/wheel retainer.