
GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
Lighting 183
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. SeeFuses0393.
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. The message TURN
SIGNAL ON will also appear in the
Driver Information Center (DIC). To
turn the chime and message off,
move the turn signal lever to the off
position.Fog Lamps
If equipped, the control is on the
center of the exterior lamp control,
to the left of the steering column.
The ignition must be in the ON/RUN
position for the fog lamps to
come on.
#(Fog Lamps) : 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 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.
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.
This button is on the overhead
console.
When the wiring is connected to an
auxiliary roof-mounted lamp,
pressing the bottom of the button
will activate the lamp and illuminate
an indicator light at the bottom of

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
186 Lighting
Lighting Features
Entry Lighting
Some exterior lamps and the interior
lamps turn on briefly at night, or in
areas with limited lighting, when
K
is pressed on the Remote Keyless
Entry (RKE) transmitter. When a
door is opened, the interior lamps
come on if the dome lamp control is
in the DOOR position. After about
30 seconds the exterior lamps turn
off. Entry lighting can be disabled
manually by changing the ignition
out of the OFF position, or by
pressing the RKE transmitter
Q
button.
This feature can be changed. See
“Vehicle Locator Lights”under
Vehicle Personalization 0167.
Exit Lighting
Some exterior lamps and the interior
lamps come on at night, or in areas
with limited lighting when the key is
removed from the ignition. The
exterior and interior lamps remain
on for a set amount of time and then automatically turn off. The interior
lamps do not come on if the dome
lamp control is in the Off position.
The exterior lamps turn off
immediately by turning the exterior
lamps control off.
This feature can be changed. See
Vehicle Personalization
0167.
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
244 Climate Controls
TEMP (Temperature Control) :
Turn clockwise or counterclockwise
to increase or decrease the
temperature inside the vehicle.
9(Fan Control) :Turn clockwise
or counterclockwise to increase or
decrease the fan speed. Turn the
knob all the way counterclockwise
to turn the fan off.
Air Delivery Mode Controls :
Press
Y,\,[, or-to change
the direction of the airflow. An
indicator light comes on in the
selected mode button.
Y(Vent) : Air is directed to the
instrument panel outlets.
\(Bi-Level) : Air is divided
between the instrument panel and
floor outlets.
[(Floor) : Air is directed to the
floor outlets, with some air directed
to the windshield, side window, and
second row floor outlets.
-(Defog) : This mode clears the
windows of fog or moisture. Air is
directed to the windshield, floor
outlets, and side window vents.
0(Defrost) : Press to clear the
windshield of fog or frost more
quickly. Air is directed to the
windshield and the side window
vents. The system automatically
forces outside air into the vehicle.
Do not drive the vehicle until all the
windows are clear.
See Air Vents 0250.
@(Recirculation) : 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-9955992) - 2017 - crc - 4/18/17
Climate Controls 245
Climate Control Systems (with Air Conditioning)
With this system the heating, cooling, and ventilation can be controlled.
1. Fan Control
2. A/C (Air Conditioning)
3. Air Delivery Mode Controls
4. Defrost
5. TEMP (Temperature Control)
6.
K(Rear Window Defogger, If
Equipped)
f(Outside Heated Mirror, If
Equipped)
8(Outside Air, If Equipped) 7.
@Air Recirculation
TEMP (Temperature Control) :
Turn clockwise or counterclockwise
to increase or decrease the
temperature inside the vehicle.
9(Fan Control) : Turn clockwise
or counterclockwise to increase or
decrease the fan speed. Turn the
knob all the way counterclockwise
to turn the fan off. Air Delivery Mode Controls :
Press
Y,\,[, or-to change
the direction of the airflow. An
indicator light comes on in the
selected mode button.
Y(Vent) : Air is directed to the
instrument panel outlets.
\(Bi-Level) : Air is divided
between the instrument panel and
floor outlets.
[(Floor) : Air is directed to the
floor outlets, with some air directed
to the windshield and side window
outlets.
-(Defog) : This mode clears the
windows of fog or moisture. Air is
directed to the windshield, floor
outlets, and side window vents.
0(Defrost) : Press to clear the
windshield of fog or frost more
quickly. Air is directed to the
windshield and the side window
vents. The system automatically
forces outside air into the vehicle
and the air conditioning compressor
will run, unless the outside
temperature is close to freezing.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
246 Climate Controls
Do not drive the vehicle until all the
windows are clear.
SeeAir Vents 0250.
@(Recirculation) : 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.
8(Outside Air, If Equipped) :
Press to turn the outside air mode
on. An indicator light on the button
comes on to show that outside is
on. When selected, air from outside
the vehicle circulates throughout the
vehicle. The recirculation mode
cannot be used with the outside
air mode.
A/C (Air Conditioning) : Press to
turn the air conditioning system 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
K(Rear Window Defogger) :
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 ignition is in ON/
RUN. The defogger turns off if the
ignition is turned to ACC/
ACCESSORY or LOCK/OFF.
If equipped with heated outside
mirrors, they turn on when the rear
window defogger button is on. They
help to clear fog or frost from the
surface of the mirrors. See Heated
Mirrors 048.
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
With this system the heating,
cooling, and ventilation in the
vehicle can be controlled.
For an eAssist vehicle, see the
Silverado/Sierra eAssist
supplement.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
Climate Controls 247
1. Driver Temperature Control
2. A/C (Air Conditioning)
3. Air Delivery Mode Controls
4. Fan Control
5. Defrost
6. Passenger TemperatureControl
7. SYNC (Synchronized Temperature)
8. Rear Window Defogger
9. Power Button
10. Air Recirculation
11. AUTO (Automatic Operation) 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 the indicator light is on, the
system is in full automatic operation.
If the air delivery mode or fan
setting is manually adjusted, the
auto indicator turns off and displays
will show the selected settings.To place the system in
automatic mode:
1. Press AUTO.
2. Set the driver and passenger temperature.
To find your comfort setting,
start with 22 °C (72 °F) and
allow the system time to
stabilize. Then 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.
The recirculation light will not come
on when automatically controlled.
Press
@to manually select
recirculation; press it again to select
outside air.
Do not cover the solar sensor on the
top of the instrument panel near the
windshield. This sensor regulates
air temperature based on sun load.
See “Sensors” later in this section.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
248 Climate Controls
Manual Operation
O:Press to turn the climate control
system on or off. When off is
selected, the system will stop air
from flowing into the cabin. If on is
selected, any other button press
occurs, or a knob is turned, the
climate control system will turn on
and operate to the current setting.
9: Turn clockwise or
counterclockwise to increase or
decrease the fan speed. Press the
knob to turn the fan off.
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.
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
is off.
The driver side or passenger side
temperature display shows the
temperature setting increasing or
decreasing.
Air Delivery Mode Control :
PressY,\,[, or-to change
the direction of the airflow. 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.
Y: Air is directed to the instrument
panel outlets.
\: Air is divided between the
instrument panel and floor outlets.
Some air is directed toward the
windshield and side window outlets.
[: Air is directed to the floor
outlets, with some to the windshield,
side window outlets, and second
row floor outlets.
-: This mode clears the windows
of fog or moisture. Air is directed to
the windshield, floor outlets, and
side window vents. The system
automatically forces outside air into
the vehicle and the air conditioning
compressor will run, unless the
outside temperature is close to
freezing.
0: Press to clear the windshield
of fog or frost more quickly. Air is
directed to the windshield and the
side window vents. The air
conditioning compressor also comes
on, unless the outside temperature
is below freezing.
Do not drive the vehicle until all
windows are clear.
See Air Vents 0250.
A/C : Press to turn the air
conditioning system 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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
Climate Controls 249
@: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. The air
conditioning compressor also comes
on when this mode is activated.
Rear Window Defogger
The rear window defogger uses a
warming grid to remove fog from the
rear window.
K: 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 ignition is in ON/
RUN. The defogger turns off if the
ignition is turned to ACC/
ACCESSORY or LOCK/OFF.
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.
Heated Mirror : If equipped with
heated outside rearview mirrors,
press
Kto heat the mirrors. See
Heated Mirrors 048.
Sensors
The solar sensor, located in the
defrost grille in the middle of the
instrument panel, monitors the solar
heat. Do not cover the solar sensor
or the system will not work properly.
There is also an exterior
temperature sensor behind the front
grille. This sensor reads the outside
air temperature and helps maintain
the temperature inside the vehicle.
Any cover on the front of the vehicle
including a snow plow, could cause
a false reading in the displayed
temperature.
Some vehicles may have the
exterior temperature sensor in the
passenger side mirror instead of the
front grille area.
The climate control system uses the
information from these sensors to
maintain comfort settings by
adjusting the outlet temperature, fan
speed, and the air delivery mode.
The system may also supply cooler
air to the side of the vehicle facing
the sun. The recirculation mode will
also be used as needed to maintain
cool outlet temperatures.