
GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/15/18
190 Climate Controls Caution (Continued)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.
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)
10. AUTO (Automatic Operation)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/15/18
Climate Controls 191Climate 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) 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. See the infotainment
manual.
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/18/18
192 Climate Controls 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.
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.
0 MAX : 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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/18/18
Climate Controls 193Avoid 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
1 REAR : 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
1 REAR to turn
them on or off. See Heated Mirrors
0 58 .
CautionUsing 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 0 43 , Heated and
Ventilated Front Seats 0 75 , and
Heated Steering Wheel 0 131 . Sensors
The solar sensor, on top of the
instrument panel near the
windshield, monitors the solar heat.
The climate control system uses the
sensor information to adjust the
temperature, fan speed,
recirculation, and air delivery mode
for best comfort.
Do not cover the sensor; otherwise
the automatic climate control system
may not work properly.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/15/18
194 Climate Controls
Air Vents Use the sliding knobs on the center
and side air vents to change the
direction of the airflow.
Air vents blow warm air on the side
windows in cold weather. If Floor,
Defog, or Defrost modes are
selected, a small amount of air will
come from the vents close to the
window.
To close the front a/c vents, move
the sliding knobs to the full down
position.
To close the rear a/c vents, move
the sliding knobs to the full inboard
position.
Operation Tips
.
Clear away any ice, snow,
or leaves from air inlets at the
base of the windshield that could
block the flow of air into the
vehicle.
.
Clear snow off the hood to
improve visibility and help
decrease moisture drawn into
the vehicle. .
Keep the path under the front
seats clear of objects to help
circulate the air inside of the
vehicle more effectively.
.
Use of non-GM approved hood
deflectors can adversely affect
the performance of the system.
Check with your dealer before
adding equipment to the outside
of the vehicle.
Maintenance Passenger Compartment
Air Filter The filter reduces the dust, pollen,
and other airborne irritants from
outside air that is pulled into the
vehicle.
The filter should be replaced as part
of routine scheduled maintenance.
See Maintenance Schedule 0 415 .
To find out what type of filter to use,
see Maintenance Replacement
Parts 0 427 .

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/15/18
Climate Controls 1951. Open the lower glove box door
completely.
2. Press the sides of the glove
box door inward and rotate the
door downward to remove. 3. Pull lever on left side of the
filter door and slide left, then
remove the door. Remove the
old filter.
4. Install the new air filter.
5. Reinstall the filter door.
6. Reverse the steps to reinstall
the glove box.
See your dealer if additional
assistance is needed. Service All vehicles have a label underhood
that identifies the refrigerant used in
the vehicle. The refrigerant system
should only be serviced by trained
and certified technicians. The air
conditioning evaporator should
never be repaired or replaced by
one from a salvage vehicle.
It should only be replaced by a new
evaporator to ensure proper and
safe operation.
During service, all refrigerants
should be reclaimed with proper
equipment. Venting refrigerants
directly to the atmosphere is harmful
to the environment and may also
create unsafe conditions based on
inhalation, combustion, frostbite,
or other health-based concerns.
The air conditioning system requires
periodic maintenance. See
Maintenance Schedule 0 415 .

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/16/18
Driving and Operating 197Fuel Top Tier Fuel . . . . . . . . . . . . . . . . . 271
Recommended Fuel (Except
6.2L V8 Engine) . . . . . . . . . . . . . 271
Recommended Fuel (6.2L
V8 Engine) . . . . . . . . . . . . . . . . . . 271
Prohibited Fuels . . . . . . . . . . . . . . 272
Fuels in Foreign Countries . . . 272
Fuel Additives . . . . . . . . . . . . . . . . 272
E85 or FlexFuel . . . . . . . . . . . . . . 272
Filling the Tank . . . . . . . . . . . . . . . 273
Filling a Portable Fuel
Container . . . . . . . . . . . . . . . . . . . 275
Trailer Towing General Towing
Information . . . . . . . . . . . . . . . . . . 276
Driving Characteristics and
Towing Tips . . . . . . . . . . . . . . . . . 276
Trailer Towing . . . . . . . . . . . . . . . . 281
Towing Equipment . . . . . . . . . . . . 285
Trailer Sway Control (TSC) . . . 293
Trailering App . . . . . . . . . . . . . . . . 296
Conversions and Add-Ons Add-On Electrical
Equipment . . . . . . . . . . . . . . . . . . 306
Adding a Snow Plow or Similar
Equipment . . . . . . . . . . . . . . . . . . 307
Pickup Conversion to
Chassis Cab . . . . . . . . . . . . . . . . 310 Driving Information Distracted Driving Distraction comes in many forms
and can take your focus from the
task of driving. Exercise good
judgment and do not let other
activities divert your attention away
from the road. Many local
governments have enacted laws
regarding driver distraction. Become
familiar with the local laws in
your area.
To avoid distracted driving, keep
your eyes on the road, keep your
hands on the steering wheel, and
focus your attention on driving.
.
Do not use a phone in
demanding driving situations.
Use a hands-free method to
place or receive necessary
phone calls.
.
Watch the road. Do not read,
take notes, or look up
information on phones or other
electronic devices. .
Designate a front seat
passenger to handle potential
distractions.
.
Become familiar with vehicle
features before driving, such as
programming favorite radio
stations and adjusting climate
control and seat settings.
Program all trip information into
any navigation device prior to
driving.
.
Wait until the vehicle is parked
to retrieve items that have fallen
to the floor.
.
Stop or park the vehicle to tend
to children.
.
Keep pets in an appropriate
carrier or restraint.
.
Avoid stressful conversations
while driving, whether with a
passenger or on a cell phone.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/16/18
Driving and Operating 207freezing rain begins to fall. Avoid
driving on wet ice or in freezing rain
until roads can be treated.
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. See
Traction Control/Electronic
Stability Control 0 243 .
.
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) 0 240 .
.
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.
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 0 437 . 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.
(Continued) Warning (Continued) If the vehicle is stuck in snow:
.
Clear snow from the base of
the vehicle, especially any
blocking the exhaust pipe.
.
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 0 228 .
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.