lights GMC SIERRA 2020 User Guide

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
168 Lighting
When the high-beam headlamps are
on, this indicator light on the
instrument cluster will also be on.
Flash-to-Pass
This feature lets you use the
high-beam headlamps to signal a
driver in front of you that you want
to pass. It works even if the
headlamps are in the automatic
position.
To use it, pull the turn signal lever
toward you, then release it.
If the headlamps are in the
automatic position or on low beam,
the high-beam headlamps will turn
on. Depending on the type of
headlamp, they will either turn off
after a short duration or stay on as
long as you hold the lever toward
you. The high-beam indicator on theinstrument cluster will come on.
Release the lever to return to
normal operation.
Daytime Running
Lamps (DRL)
DRL can make it easier for others to
see the front of the vehicle during
the day. Fully functional DRL are
required on all vehicles first sold in
Canada.
The DRL system comes on when
the following conditions are met:
.
The ignition is on.
. The exterior lamp control is
in AUTO.
. The transmission is not in
P (Park).
. The light sensor determines it is
daytime.
When the DRL system is on, only
the DRL are on. The taillamps,
sidemarker lamps, instrument panel
lights, and other lamps will not
be on. When it begins to get dark, the
automatic headlamp system
switches from DRL to the
headlamps.
To turn off the DRL, turn the exterior
lamp control to
Oand then release.
For vehicles first sold in Canada, off
will only work when the vehicle is
parked.
Automatic Headlamp
System
When the exterior lamp control is
set to AUTO and it is dark enough
outside, the headlamps come on
automatically.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Lighting 169
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 instrumentcluster may not be as bright as
usual. Make sure the instrument
panel illumination control is in the
full bright position. See
Instrument
Panel Illumination Control 0172.
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
O
or;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 Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
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.
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

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
172 Lighting
- 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 - 4/4/19
Lighting 173
+ON/OFF : Press to turn the dome
lamps on manually. Press again to
turn the dome lamps off.
Reading Lamps
There are reading lamps on the
overhead console and over the rear
seats. These lamps come on when
any door is opened.
Front Reading Lamps
The front reading lamps are in the
overhead console.
Press the lamp lenses to turn the
front reading lamps on or off.
Rear Reading Lamps
The rear reading lamps are over the
rear seats.
Press the lamp lens to turn the rear
reading lamps on or off.
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. 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
Qbutton.
This feature can be changed. See
“Vehicle Locator Lights” under
Vehicle Personalization 0157.
Exit Lighting
Some exterior lamps and interior
lights come on at night, or in areas
with limited lighting, when the driver
door is opened after the ignition is
turned off. The dome lamp comes
on after the ignition is turned off.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 209
Remote Keyless Entry (RKE)
System Operation (Keyless Access)
015.
To shift out of P (Park), the ignition
must be on or in Service Mode, and
the brake pedal must be applied.
{Warning
Turning off the vehicle while
moving may cause loss of power
assist in the brake and steering
systems and disable the airbags.
While driving, only shut the
vehicle off in an emergency.
Stopping the Engine/LOCK/
OFF (No Indicator Lights) : When
the vehicle is stopped, press
ENGINE START/STOP once to turn
the engine off.
If the vehicle is in P (Park), the
ignition will turn off, and Retained
Accessory Power (RAP) will remain
active. See Retained Accessory
Power (RAP) 0217. If the vehicle is not in P (Park), the
ignition will return to ACC/
ACCESSORY and display the
message SHIFT TO PARK in the
Driver Information Center (DIC).
When the vehicle is shifted into
P (Park), the ignition system will
turn off.
The vehicle may have an electric
steering column lock. The lock is
activated when the ignition is turned
off and driver door is opened.
A sound may be heard as the lock
actuates or releases. The steering
column lock may not release with
the wheels turned off center. If this
happens, the vehicle may not start.
Move the steering wheel from left to
right while attempting to start the
vehicle. If this does not work, the
vehicle needs service.
Unless an emergency exists, do not
turn the engine off when the vehicle
is moving. This will cause a loss of
power assist in the brake and
steering systems and disable the
airbags.
If the vehicle must be shut off in an
emergency: 1. If the vehicle cannot be pulled
over, and must be shut off
while driving, press and hold
ENGINE START/STOP button
for longer than two seconds,
or press twice in five seconds.
2. Brake using a firm and steady pressure. Do not pump the
brakes repeatedly. This may
deplete power assist, requiring
increased brake pedal force.
3. Shift the vehicle to N (Neutral). This can be done while the
vehicle is moving. After shifting
to N (Neutral), firmly apply the
brakes and steer the vehicle to
a safe location.
4. Come to a complete stop, shift to P (Park) with an automatic
transmission, or Neutral with a
manual transmission, and
make sure engine is off. On
vehicles with an automatic
transmission, the shift lever
must be in P (Park) to turn the
ignition off.
5. Set the parking brake. See Electric Parking Brake 0233.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
212 Driving and Operating
5. Shift to P (Park) with anautomatic transmission, or stay
in Neutral with a manual
transmission.
6. Push the key all the way in toward the steering column (1),
then turn the ignition to
LOCK/OFF (2).
7. Set the parking brake. See Electric Parking Brake 0233.
8. Remove the key.
9. Release the brake pedal.
Caution
Use the correct key, make sure it
is all the way in —or pushed all
the way in toward the steering
column when turning off the
vehicle —and turn it only with
your hand.
1 (ACC/ACCESSORY) : This
position allows features such as the
infotainment system to operate
while the vehicle is off. It also
unlocks the steering column, if equipped with a locking steering
column. Use this position if the
vehicle must be pushed or towed.
See
Retained Accessory Power
(RAP) 0217.
From ON/RUN, push the key all the
way in toward the steering column,
then turn the key to ACC/
ACCESSORY.
If the key is left in ACC/
ACCESSORY with the engine off,
the battery could drain and the
vehicle may not start.
A warning chime will sound when
the driver door is opened and the
key is in the ignition.
2 (ON/RUN) : This position can be
used to operate the electrical
accessories and to display some
instrument cluster warning and
indicator lights. This position can
also be used for service and
diagnostics, and to verify the proper
operation of the malfunction
indicator lamp as may be required
for emission inspection purposes.
The switch stays in this position when the engine is running. The
transmission is also unlocked in this
position.
If the key is left in ON/RUN with the
engine off, the battery could drain
and the vehicle may not start.
3 (START) :
This is the position that
starts the engine. When the engine
starts, release the key. The ignition
returns to ON/RUN for driving.
Starting the Engine
If the vehicle has a diesel engine,
see the Duramax diesel
supplement.
Caution
If you add electrical parts or
accessories, you could change
the way the engine operates. Any
resulting damage would not be
covered by the vehicle warranty.
See Add-On Electrical Equipment
0 322.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
250 Driving and Operating
When pressed, the current gap
setting displays briefly on the
instrument cluster. The gap setting
will be maintained until it is
changed.
Since each gap setting corresponds
to a following time (Far, Medium,
or Near), the following distance will
vary based on vehicle speed. The
faster the vehicle speed, the further
back your vehicle will follow a
vehicle detected ahead. Consider
traffic and weather conditions when
selecting the following gap. The
range of selectable gaps may not be
appropriate for all drivers and
driving conditions.
Changing the gap setting
automatically changes the alert
timing sensitivity (Far, Medium,
or Near) for the Forward Collision
Alert (FCA) feature. SeeForward
Collision Alert (FCA) System 0268. Alerting the Driver
With Head-Up Display
Without Head-Up Display
If ACC is engaged, driver action
may be required when ACC cannot
apply sufficient braking because of
approaching a vehicle too rapidly.
When this condition occurs, six red
lights will flash on the windshield.
Either eight beeps will sound from
the front, or both sides of the Safety
Alert Seat will pulse five times. See
“Collision/Detection Systems” under
Vehicle Personalization 0157.
See Defensive Driving 0187. Approaching and Following a
Vehicle
The vehicle ahead indicator is in the
instrument cluster. It only displays
when a vehicle is detected in your
vehicle’s path moving in the same
direction. If this symbol is not
displaying, ACC will not respond to
or brake for vehicles ahead.
ACC automatically slows the vehicle
down and adjusts vehicle speed to
follow a detected vehicle ahead at
the selected following gap. The
vehicle speed increases or
decreases to follow a detected
vehicle in front of your vehicle when
that vehicle is traveling slower than
your vehicle set speed. It may apply
limited braking, if necessary. When
braking is active, the brake lamps
will come on. The automatic braking

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
268 Driving and Operating
to the button comes on when the
features are on and turns off when
the features have been disabled.
Front and Rear Park Assist can be
turned Off, On, or On with Towbar.
See“Park Assist” underVehicle
Personalization 0157. If Park Assist
is turned off through vehicle
personalization, the Park Assist
button will be disabled. To turn Park
Assist on again, select On in vehicle
personalization. The On with Towbar
setting allows Park Assist to work
properly with a trailer hitch. Some
larger trailer hitches may not be
compatible.
Turn off Park Assist when towing a
trailer.
To turn the RPA symbols on or off,
see “Rear Camera Park Assist
Symbols” underVehicle
Personalization 0157.
Assistance Systems for
Driving
If equipped, when driving the
vehicle in a forward gear, Forward
Collision Alert (FCA), Lane Departure Warning (LDW), Lane
Keep Assist (LKA), Side Blind Zone
Alert (SBZA), Lane Change Alert
(LCA), Automatic Emergency
Braking (AEB), and/or the Front
Pedestrian Braking (FPB) System
can help to avoid a crash or reduce
crash damage.
Forward Collision Alert
(FCA) System
If equipped, the FCA system may
help to avoid or reduce the harm
caused by front-end crashes. When
approaching a vehicle ahead too
quickly, FCA provides a red flashing
alert on the windshield and rapidly
beeps or pulses the driver seat.
FCA also lights an amber visual
alert if following another vehicle
much too closely.
FCA detects vehicles within a
distance of approximately 60 m
(197 ft) and operates at speeds
above 8 km/h (5 mph).
{Warning
FCA is a warning system and
does not apply the brakes. When
approaching a slower-moving or
stopped vehicle ahead too rapidly,
or when following a vehicle too
closely, FCA may not provide a
warning with enough time to help
avoid a crash. It also may not
provide any warning at all. FCA
does not warn of pedestrians,
animals, signs, guardrails,
bridges, construction barrels,
or other objects. Be ready to take
action and apply the brakes. See
Defensive Driving
0187.
FCA can be disabled through
vehicle personalization. See
“Collision/Detection Systems” under
Vehicle Personalization 0157.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 275
Warning (Continued)
provide alerts when changing
lanes under all driving conditions.
Failure to use proper care when
changing lanes may result in
injury, death, or vehicle damage.
Before making a lane change,
always check mirrors, glance over
your shoulder, and use the turn
signals.
LCA Detection Zones
1. SBZA Detection Zone
2. LCA Detection Zone
The LCA sensor covers a zone of
approximately one lane over from
both sides of the vehicle, or 3.5 m (11 ft). The height of the zone is
approximately between 0.5 m (1.5 ft)
and 2 m (6 ft) off the ground. The
Side Blind Zone Alert (SBZA)
warning area starts at approximately
the middle of the vehicle and goes
back 5 m (16 ft). Drivers are also
warned of vehicles rapidly
approaching from up to 25 m (82 ft)
behind the vehicle.
How the System Works
The LCA symbol lights up in the
side mirrors when the system
detects a moving vehicle in the next
lane over that is in the side blind
zone or rapidly approaching that
zone from behind. A lit LCA symbol
indicates it may be unsafe to
change lanes. Before making a lane
change, check the LCA display,
check mirrors, glance over your
shoulder, and use the turn signals.
Left Side Mirror
DisplayRight Side Mirror Display
When the vehicle is started, both
outside mirror LCA displays will
briefly come on to indicate the
system is operating. When the
vehicle is in a forward gear, the left
or right side mirror display will light
up if a moving vehicle is detected in
the next lane over in that blind zone
or rapidly approaching that zone.
If the turn signal is activated in the
same direction as a detected
vehicle, this display will flash as an
extra warning not to change lanes.
LCA is disabled when the trailer
connection status is displayed.
A DIC message may display. The
SBZA system still operates.
LCA can be disabled through
vehicle personalization. When you
disable LCA, SBZA is also disabled.