2023 GMC SIERRA headlamp

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
142 Lighting
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 0145.
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.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Lighting 143
Turn and Lane-Change Signals
An arrow on the instrument cluster flashes
in the direction of the turn or lane change.
Move the turn signal lever all the way up or
down to signal a turn.
Partially raise or lower the lever for less
than one second until the arrow starts to
flash to signal a lane change. This causes
the turn signals to automatically flash three
times. It will flash six times if Tow/Haul
Mode is active. Holding the turn signal lever
for more than one second will cause the
turn signals to flash until the lever is
released.The lever returns to its starting position
whenever it is released.
If after signaling a turn or a lane change the
arrows flash rapidly or do not come on, a
signal bulb could be burned out. If equipped
with LED turn signals, see your dealer.
Replace any burned out bulbs. If a bulb is
not burned out, check the fuse. See
Fuses
and Circuit Breakers 0329.
Turn Signal On Chime
If the turn signal is left on for more than
1.2 km (0.75 mi), a chime sounds at each
flash of the turn signal. A message may
appear in the Driver Information Center
(DIC). See Vehicle Messages 0135. To turn
the chime and message off, move the turn
signal lever to the off position.
Fog Lamps
If equipped, the fog lamp control is near the
exterior lamp control to the left of the
steering column.
The vehicle must be on for the fog lamps to
come on.
#: Press to turn the fog lamps on or off.
A light will come on in the instrument
cluster.
When the fog lamps are turned on, the
parking lamps automatically turn on.
When the headlamps are changed to high
beam, the fog lamps also go off. When the
high-beam headlamps are turned off, the fog
lamps will come on again.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
144 Lighting
Some localities have laws that require the
headlamps to be on with the fog lamps.
Task Lighting
If equipped, task lighting projects light from
the outside mirrors away from the vehicle.
While the vehicle is parked, press
Kto
select one of the following options:
.Left and Right Task Lights Illuminated
.Left Task Light Illuminated
.Right Task Light Illuminated
.Left and Right Task Lights Off
If the vehicle leaves a parked position, the
lights will immediately turn off. If the vehicle is off, the lights will stay on
for approximately 10 minutes.
If any Task lights are on, if the button has
not been pressed after approximately
5 seconds, pressing it again will turn off all
Task Lights.
Auxiliary Roof-Mounted Lamp
If equipped, this button includes wiring
provisions for a dealer or a qualified service
center to install an auxiliary roof lamp.
For information on roof-mounted emergency
lamp installation, see www.gmupfitter.com
or contact your dealer.
If the vehicle has this button, the vehicle
may have the snow plow prep package. See
Add-On Electrical Equipment
0297.
Exterior Cargo Lamps
The cargo lamps provide more light in the
cargo area or on the sides of the vehicle,
if needed. The lamps inside the pickup box,
in the tailgate handle, for the hitch, and/or
the cargo mirror lamps also turn on,
if equipped.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Lighting 145
If the vehicle is in P (Park), R (Reverse),
or N (Neutral) the Cargo Lamp Switch causes
the lights to cycle through the following
states for each button press:
Initial Press
‐Center High Mounted Stop Lamp
(CHMSL)/Cargo Bed Lights –On
‐ Cargo Mirror Lights –On
‐ Cargo Switch Indicator (if equipped) –On
Next Press (if within 5 seconds of the
previous button press)
‐ CHMSL/Cargo Bed Lights –On
‐ Cargo Mirror Lights –Off
‐ Cargo Switch Indicator (if equipped) –On
Next Press
‐ CHMSL/Cargo Bed Lights –Off
‐ Cargo Mirror Lights –Off
‐ Cargo Switch Indicator (if equipped) –Off
Become familiar with and follow all state
and local laws that apply to cargo lamp
operation.Interior Lighting
Instrument Panel Illumination
Control
This feature adjusts the brightness of all
illuminated controls. The instrument panel
illumination control is next to the exterior
lamp control.
D: PressD− to dim or +Dto brighten
the lights.
This feature is functional at night, or when
the headlamps or parking lamps are on.
Dome Lamps
The dome lamp controls are in the overhead
console.
The dome lamps come on when any door is
opened,
Kon the remote key is pressed,
or when the vehicle is turned off.
To operate, press the following buttons:
jOFF : Press to turn off the dome
lamps. An indicator light on the button will
turn on when the dome lamp override is
activated. Press
jOFF again to
deactivate this feature and the indicator
light will turn off.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Lighting 147
Battery Load Management
The vehicle has Electric Power Management
(EPM), which estimates the battery's
temperature and state of charge. It then
adjusts the voltage for best performance
and extended life of the battery.
When the battery's state of charge is low,
the voltage is raised slightly to quickly bring
the charge back up. When the state of
charge is high, the voltage is lowered
slightly to prevent overcharging. The
voltmeter gauge or the voltage display on
the Driver Information Center (DIC),
if equipped, may show the voltage moving
up or down. This is normal. If there is a
problem, an alert will be displayed.
The battery can be discharged at idle if the
electrical loads are very high. This is true for
all vehicles. This is because the generator
(alternator) may not be spinning fast
enough at idle to produce all the power that
is needed for very high electrical loads.A high electrical load occurs when several of
the following are on, such as: headlamps,
high beams, fog lamps, rear window
defogger, climate control fan at high speed,
heated seats, engine cooling fans, trailer
loads, and loads plugged into accessory
power outlets.
EPM works to prevent excessive discharge of
the battery. It does this by balancing the
generator's output and the vehicle's
electrical needs. It can increase engine idle
speed to generate more power, whenever
needed. It can temporarily reduce the power
demands of some accessories.
Normally, these actions occur in steps or
levels, without being noticeable. In rare
cases at the highest levels of corrective
action, this action may be noticeable to the
driver. If so, a DIC message might be
displayed and it is recommended that the
driver reduce the electrical loads as much as
possible.
Battery Power Protection
This feature helps prevent the battery from
being drained, if the interior courtesy lamps
or reading lamps are accidentally left on.
If any of these lamps are left on, they
automatically turn off after 10 minutes,
if the ignition is off. The lamps will not
come back on again until one of the
following occurs:
.The ignition is turned on.
.The doors are closed and then re-opened.
Exterior Lighting Battery Saver
The exterior lamps turn off about 10 minutes
after the vehicle is turned off, if the parking
lamps or headlamps have been manually
left on. This protects against draining the
battery. To restart the 10-minute timer, turn
the exterior lamp control to the
Oposition
and then back to the
;or2position.
To keep the lamps on for more than
10 minutes, the vehicle must be on or in
accessory mode.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Driving and Operating 209
Driving on Hills
Driving safely on hills requires good
judgment and an understanding of what the
vehicle can and cannot do.
{Warning
Many hills are simply too steep for any
vehicle. Driving up hills can cause the
vehicle to stall. Driving down hills can
cause loss of control. Driving across hills
can cause a rollover. You could be injured
or killed. Do not drive on steep hills.
Before driving on a hill, assess the
steepness, traction, and obstructions. If the
terrain ahead cannot be seen, get out of the
vehicle and walk the hill before driving
further.
When driving on hills:
.Use a low gear and keep a firm grip on
the steering wheel.
.Maintain a slow speed.
.When possible, drive straight up or down
the hill.
.Slow down when approaching the top of
the hill.
{Warning
Driving to the top of a hill at high speed
can cause a crash. There could be a
drop-off, embankment, cliff, or even
another vehicle. You could be seriously
injured or killed. As you near the top of a
hill, slow down and stay alert.
.Use headlamps even during the day to
make the vehicle more visible.
.Avoid turns that take the vehicle across
the incline of the hill. Driving across an
incline puts more weight on the downhill
wheels, which could cause a downhill
slide or a rollover.
.Loose gravel, muddy spots, or even wet
grass can cause the tires to slip sideways,
downhill. If the vehicle slips sideways, it
can hit something and potentially
roll over.
.Hidden obstacles can make the steepness
of the incline more severe. If a rock is
driven across with the uphill wheels, or if
the downhill wheels drop into a rut or
depression, the vehicle can tilt even more.
.If an incline must be driven across, and
the vehicle starts to slide, turn downhill.
This should help straighten out the
vehicle and prevent the side slipping.
.Never go downhill forward or backward
with either the transmission or transfer
case in N (Neutral). The brakes could
overheat and you could lose control.
.When driving down a hill, keep the
vehicle headed straight down. Use a low
gear because the engine will work with
the brakes to slow the vehicle and help
keep the vehicle under control.
{Warning
If the vehicle has the two-speed
automatic transfer case, shifting the
transfer case to N (Neutral) can cause
your vehicle to roll even if the
transmission is in P (Park). This is because
the N (Neutral) position on the transfer
case overrides the transmission. You or
someone else could be injured. If leaving
the vehicle, set the parking brake and
shift the transmission to P (Park). Shift
the transfer case to any position but
N (Neutral).

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Driving and Operating 213
For Slippery Road Driving:
.Accelerate gently. Accelerating too quickly
causes the wheels to spin and makes the
surface under the tires slick.
.Turn on Traction Control. SeeTraction
Control/Electronic Stability Control 0241.
.The Antilock Brake System (ABS) improves
vehicle stability during hard stops, but
the brakes should be applied sooner than
when on dry pavement. See Antilock
Brake System (ABS) 0238.
.Allow greater following distance and
watch for slippery spots. Icy patches can
occur on otherwise clear roads in shaded
areas. The surface of a curve or an
overpass can remain icy when the
surrounding roads are clear. Avoid sudden
steering maneuvers and braking while
on ice.
.Turn off cruise control.
Cold Weather Mode
In very low temperatures, a cold weather
message may display on the Driver
Information Center (DIC). The engine speed,
transmission shift patterns, and cabin fan
speed may operate differently to enable the vehicle to warm up quicker. You can
manually override the cabin fan speed in
cold weather mode.
Blizzard Conditions
Stop the vehicle in a safe place and signal
for help. Stay with the vehicle unless there
is help nearby. If possible, use Roadside
Assistance. See
Roadside Assistance Program
0 399. To get help and keep everyone in
the vehicle safe:
.Turn on the hazard warning flashers.
.Tie a red cloth to an outside mirror.
{Warning
Snow can trap engine exhaust under the
vehicle. This may cause exhaust gases to
get inside. Engine exhaust contains
carbon monoxide (CO), which cannot be
seen or smelled. It can cause
unconsciousness and even death.
If the vehicle is stuck in snow:
.Clear snow from the base of the
vehicle, especially any blocking the
exhaust pipe.
(Continued)
Warning (Continued)
.Open a window about 5 cm (2 in) on
the vehicle side that is away from the
wind, to bring in fresh air.
.Fully open the air outlets on or under
the instrument panel.
.Adjust the climate control system to
circulate the air inside the vehicle and
set the fan speed to the highest
setting. See“Climate Control Systems.”
For more information about CO, see
Engine Exhaust 0229.
To save fuel, run the engine for short
periods to warm the vehicle and then shut
the engine off and partially close the
window. Moving about to keep warm also
helps.
If it takes time for help to arrive, when
running the engine, push the accelerator
pedal slightly so the engine runs faster than
the idle speed. This keeps the battery
charged to restart the vehicle and to signal
for help with the headlamps. Do this as
little as possible, to save fuel.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Driving and Operating 247
Warning (Continued)
Complete attention is always required
while driving, and you should be ready to
take action and apply the brakes and/or
steer the vehicle to avoid crashes.
Audible or Safety Alert Seat
Some driver assistance features alert the
driver of obstacles by beeping. To view
available settings for this feature, touch the
Settings icon on the infotainment home
page. Select “Vehicle”to display the list of
available options and select “Comfort and
Convenience”.
If equipped with the Safety Alert Seat, the
driver seat cushion may provide a vibrating
pulse alert instead of beeping. To view
available settings for this feature, touch the
Settings icon on the infotainment home
page. Select “Vehicle”to display the list of
available options and select “Collision/
Detection Systems”.
Cleaning
Depending on vehicle options, keep these
areas of the vehicle clean to ensure the best
driver assistance feature performance. Driver Information Center (DIC) messages may
display when the systems are unavailable or
blocked.
.Front and rear bumpers and the area
below the bumpers
.Front grille and headlamps
.Front camera lens in the front grille or
near the front emblem
.Front side and rear side panels
.Outside of the windshield in front of the
rearview mirror
.Side camera lens on the bottom of the
outside mirrors
.Rear side corner bumpers
.Rear Vision Camera in the tailgate handle
.Rear Camera Mirror and Cargo View
Camera in the Center High-Mounted
Stoplamp
Radio Frequency
This vehicle may be equipped with driver
assistance systems that operate using radio
frequency. See Radio Frequency Statement
0 404.