
GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
158 Instruments and Controls
Rear Cross Traffic Alert
This allows the Rear Cross Traffic
Alert feature to be turned on or off.
SeeAssistance Systems for Parking
or Backing 0257.
Touch Off or On.
Comfort and Convenience
Touch and the following may
display:
. Chime Volume
. Reverse Tilt Mirror
. Remote Mirror Folding
Chime Volume
This determines the chime volume
level.
Touch the controls on the
infotainment display to adjust the
volume.
Reverse Tilt Mirror
This allows the feature to be turned
on or off. See Reverse Tilt Mirrors
0 44. Touch Off, On - Driver and
Passenger, On - Driver, or On -
Passenger.
Remote Mirror Folding
When on, the outside mirrors will
remotely fold or unfold when the
Remote Keyless Entry (RKE)
transmitterQorKbutton is
pressed and held. See Folding
Mirrors 042.
Touch Off or On.
Lighting
Touch and the following may
display:
. Vehicle Locator Lights
. Exit Lighting
Vehicle Locator Lights
This setting flashes the vehicle’ s
headlamps when
Kis pressed on
the Remote Keyless Entry (RKE)
transmitter.
Touch Off or On. Exit Lighting
This setting specifies how long the
headlamps stay on after the vehicle
is turned off and exited.
Touch Off, 30 Seconds, 60 Seconds,
or 120 Seconds.
Power Door Locks
Touch and the following may
display:
.
Open Door Anti Lock Out
. Auto Door Unlock
. Delayed Door Lock
Open Door Anti Lock Out
This setting prevents the driver door
from locking when the door is open.
If this setting is on, the Delayed
Door Lock menu will not be
available.
Touch Off or On.
Auto Door Unlock
This setting allows selection of
which doors will automatically
unlock when the vehicle is shifted
into P (Park).

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Lighting 171
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.
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.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 Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
172 Lighting
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:
- CHMSL/Cargo Bed Lights - On
- Cargo Mirror Lights - On
- Cargo Switch Indicator (if
equipped) - On
- Next Press: (if with in 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 controls the brightness
of the steering wheel and instrument
panel lights. The instrument panel
illumination control is next to the
exterior lamp control.
D:PressD+ to brighten orD−
to dim the lights.
Dome Lamps
The dome lamp controls are in the
overhead console.
To operate, press the following
buttons:
jOFF : Press to turn off the
dome lamps when a door is open.
An indicator light on the button will
turn on when the dome lamp
override is activated. Press
j
OFF again to deactivate this feature
and the indicator light will turn off.
The dome lamps will come on when
doors are opened.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Climate Controls 177
Climate Controls
Climate Control Systems
Climate Control Systems . . . . . 177
Dual Automatic ClimateControl System . . . . . . . . . . . . . 179
Air Vents
Air Vents . . . . . . . . . . . . . . . . . . . . . 182
Maintenance
Passenger Compartment AirFilter . . . . . . . . . . . . . . . . . . . . . . . . 183
Service . . . . . . . . . . . . . . . . . . . . . . . 184
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
178 Climate Controls
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.
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 turns off if the ignition
is turned off or to ACC/
ACCESSORY.
If equipped with heated outside
mirrors, press
fto turn them on or
off. See Heated Mirrors 043.
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Climate Controls 179
Dual Automatic Climate Control System
The heating, cooling, and ventilation in the vehicle can be controlled with this
system.
1. Driver and PassengerTemperature 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 Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Climate Controls 181
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.
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 turns off if the ignition
is turned off or to ACC/
ACCESSORY.
If equipped with heated outside
mirrors, press
fto turn them on or
off. See Heated Mirrors 043.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Driving and Operating 191
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.
Off-Road Driving
Four-wheel-drive vehicles can be
used for off-road driving. Vehicles
without four-wheel drive and
vehicles not equipped with All
Terrain (AT) or On-Off Road (OOR)
tires must not be driven off-road
except on a level, solid surface. For
contact information about the
original equipment tires, see the
warranty manual.
One of the best ways for successful
off-road driving is to control the
speed.
{Warning
When driving off-road, bouncing
and quick changes in direction
can easily throw you out of
position. This could cause you to
lose control and crash. You and
your passengers should always
wear seat belts.
Before Driving Off-Road
. Have all necessary maintenance
and service work completed.
. Fuel the vehicle, fill fluid levels,
and check inflation pressure in
all tires, including the spare,
if equipped.
. Read all the information about
four-wheel-drive vehicles in this
manual.
. Remove any underbody air
deflector, if equipped. Re-attach
the air deflector after off-road
driving.
. Know the local laws that apply to
off-road driving.