2023 GMC SIERRA mirror

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
196 Climate Controls
Climate Controls
Climate Control Systems
Climate Control Systems . . . . . . . . . . . . . . 196
Dual Automatic Climate ControlSystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
Air Vents
Air Vents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
Maintenance
Passenger Compartment Air Filter . . . . . 201
Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
Climate Control Systems
The heating, cooling, and ventilation in the vehicle can be controlled with this system.
1. Fan Control
2. MAX Defrost
3. Air Delivery Mode Controls
4. A/C (Air Conditioning)
5. TEMP (Temperature Control)
6. Recirculation
7. Rear Window Defogger (If Equipped) or Heated Mirrors (If Equipped)9:Turn clockwise or counterclockwise to
increase or decrease the fan speed. Turn the
knob all the way counterclockwise to turn
the fan off.
TEMP : Turn clockwise or counterclockwise
to increase or decrease the temperature
inside the vehicle.
Air Delivery Mode Controls : 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.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Climate Controls 197
To change the current mode, select one or
more of the following. An indicator light will
illuminate:
z:Air is directed to the windshield,
outboard a/c outlets, and side window
outlets.
Y: Air is directed to the a/c outlets.
[:Air is directed to the floor outlets,
with some air directed to the windshield,
outboard a/c outlets, and side window
outlets.
0MAX : Air is directed to the windshield
and the fan runs at a higher speed if not
already above a medium fan speed. This
mode overrides the previous mode selected
and clears fog or frost from the windshield
more quickly. When the control is pressed
again, the system returns to the previous
mode setting and fan speed.
For best results, clear all snow and ice from
the windshield before defrosting.
@: Press to turn on recirculation. An
indicator light comes on. Air is recirculated
to quickly cool the inside of the vehicle.
It can also be used to help reduce outside
air and odors that enter the vehicle.
Avoid using recirculation for long periods of
time in cold or damp conditions. Using
recirculation in cold or damp conditions can
result in window fogging.
A/C : Press to turn the air conditioning on
or off. An indicator light comes on to show
that the air conditioning is enabled. If the
fan is turned off, the air conditioner will not
run. The A/C light will stay on even if the
outside temperatures are below freezing.
Rear Window Defogger
1REAR : If equipped, press to turn the
rear window defogger on or off. An indicator
light on the button comes on to show that
the rear window defogger is on.
The rear window defogger only works when
the engine is running. The defogger can be
turned off by turning the vehicle off or to
accessory mode. If equipped with heated outside mirrors,
press
fto turn them on or off. See
Heated
Mirrors 039.
Caution
Using a razor blade or sharp object to
clear the inside rear window can damage
the rear window defogger. Repairs would
not be covered by the vehicle warranty.
Do not clear the inside rear window with
sharp objects.
Dual Automatic Climate Control
System
The heating, cooling, and ventilation in the
vehicle can be controlled with this system.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
198 Climate Controls
Uplevel Shown
1. Driver and Passenger Temperature Controls
2. MAX Defrost
3. Air Delivery Mode Controls
4. A/C (Air Conditioning)
5. SYNC (Synchronized Temperature) 6. Recirculation
7. Power Button
8. Fan Control
9. Rear Window Defogger (If Equipped) or
Heated Mirrors (If Equipped)
10. AUTO (Automatic Operation)
Climate Control Display
1. Driver and Passenger Temperature Settings
2. Fan Control
3. Driver and Passenger Temperature Controls
4. Sync (Synchronized Temperature)
5. Recirculation
6. Air Delivery Mode Controls
7. Auto (Automatic Operation)
8. A/C (Air Conditioning)
9. On/Off (Power)

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
200 Climate Controls
Changing the mode cancels the automatic
operation and the system goes into manual
mode. Press AUTO to return to automatic
operation.
To change the current mode, select one or
more of the following:
z:Air is directed to the windshield,
outboard a/c outlets, and side window
outlets.
Y: Air is directed to the a/c outlets.
[:Air is directed to the floor outlets,
with some air directed to the windshield,
outboard a/c outlets, and side window
outlets.
0MAX : Air is directed to the windshield
and the fan runs at a higher speed if not
already above a medium fan speed. This
mode overrides the previous mode selected
and clears fog or frost from the windshield
more quickly. When the control is pressed
again, the system returns to the previous
mode setting and fan speed.
For best results, clear all snow and ice from
the windshield before defrosting.
@: Press to turn on recirculation. An
indicator light comes on. Air is recirculated
to quickly cool the inside of the vehicle.
It can also be used to help reduce outside
air and odors that enter the vehicle.
Avoid using recirculation for long periods of
time in cold or damp conditions. Using
recirculation in cold or damp conditions can
result in window fogging.
A/C : Press to turn the air conditioning on
or off. An indicator light comes on to show
that the air conditioning is enabled. If the
fan is turned off, the air conditioner will not
run. The A/C light will stay on even if the
outside temperatures are below freezing.
Rear Window Defogger
1REAR : If equipped, press to turn the
rear window defogger on or off. An indicator
light on the button comes on to show that
the rear window defogger is on.
The rear window defogger only works when
the engine is running.The defogger can be
turned off by turning the vehicle off or to
accessory mode.
If equipped with heated outside mirrors,
press
fto turn them on or off. See Heated
Mirrors 039.
Caution
Using a razor blade or sharp object to
clear the inside rear window can damage
the rear window defogger. Repairs would
not be covered by the vehicle warranty.
Do not clear the inside rear window with
sharp objects.
Remote Start Climate Control Operation :
If equipped with remote start, the climate
control system may run when the vehicle is
started remotely. If equipped with heated or
ventilated seats or a heated steering wheel,
these features may come on during a
remote start. See Remote Vehicle Start 022,
Heated and Ventilated Front Seats 056, and
Heated Steering Wheel 0105.
Sensors

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Driving and Operating 207
.Wait until the vehicle is out of the curve
before accelerating gently into the
straightaway.
Steering in Emergencies
.There are some situations when steering
around a problem may be more effective
than braking.
.Holding both sides of the steering wheel
allows you to turn 180 degrees without
removing a hand.
.Antilock Brake System (ABS) allows
steering while braking.
Off-Road Recovery
The vehicle's right wheels can drop off the
edge of a road onto the shoulder while
driving. Follow these tips:1. Ease off the accelerator and then, if there is nothing in the way, steer the
vehicle so that it straddles the edge of
the pavement.
2. Turn the steering wheel about one-eighth of a turn, until the right front
tire contacts the pavement edge.
3. Turn the steering wheel to go straight down the roadway.
Loss of Control
Skidding
There are three types of skids that
correspond to the vehicle's three control
systems:
.Braking Skid —wheels are not rolling.
.Steering or Cornering Skid —too much
speed or steering in a curve causes tires
to slip and lose cornering force.
.Acceleration Skid —too much throttle
causes the driving wheels to spin. Defensive drivers avoid most skids by taking
reasonable care suited to existing conditions,
and by not overdriving those conditions. But
skids are always possible.
If the vehicle starts to slide, follow these
suggestions:
.Ease your foot off the accelerator pedal
and steer the way you want the vehicle
to go. The vehicle may straighten out. Be
ready for a second skid if it occurs.
.Slow down and adjust your driving
according to weather conditions. Stopping
distance can be longer and vehicle control
can be affected when traction is reduced
by water, snow, ice, gravel, or other
material on the road. Learn to recognize
warning clues
—such as enough water,
ice, or packed snow on the road to make
a mirrored surface —and slow down
when you have any doubt.
.Try to avoid sudden steering, acceleration,
or braking, including reducing vehicle
speed by shifting to a lower gear. Any
sudden changes could cause the tires to
slide.
Remember: Antilock brakes help avoid only
the braking skid.

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.