2020 GMC SIERRA headlamp

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Lighting 167
Keep this area of the windshield
clear of debris to allow for best
system performance.
The high-beam headlamps remain
on, under the automatic control,
until one of the following situations
occurs:
.The system detects an
approaching vehicle's
headlamps.
. The system detects a preceding
vehicle's taillamps.
. The outside light is bright
enough that high-beam
headlamps are not required.
. The vehicle's speed drops below
20 km/h (12 mph).
. The IntelliBeam system is
disabled by the button on the
turn signal lever. If this happens,
press the button on the end of
the turn signal lever when the
exterior lamp control is in the
AUTO or
2position. The
instrument cluster light will come
on to indicate the IntelliBeam is reactivated. See
Headlamp
High/Low-Beam Changer 0167
and
Flash-to-Pass 0168.
The high beams may not turn off
automatically if the system cannot
detect another vehicle's lamps
because of any of the following:
. The other vehicle's lamps are
missing, damaged, obstructed
from view, or otherwise
undetected.
. The other vehicle's lamps are
covered with dirt, snow, and/or
road spray.
. The other vehicle's lamps cannot
be detected due to dense
exhaust, smoke, fog, snow, road
spray, mist, or other airborne
obstructions.
. The vehicle's windshield is dirty,
cracked, or obstructed by
something that blocks the view
of the light sensor. .
The vehicle is loaded such that
the front end points upward,
causing the light sensor to aim
high and not detect headlamps
and taillamps.
. Driving on winding or hilly roads.
The automatic high-beam
headlamps may need to be disabled
if any of the above conditions exist.
Exterior Lamps Off
Reminder
A reminder chime sounds when the
headlamps or parking lamps are
manually turned on, the ignition is
off, and a door is open. To disable
the chime, turn the lamps off.
Headlamp High/
Low-Beam Changer
Push the turn signal lever toward
the instrument panel to change the
headlamps from low to high beam.
Pull or push the turn signal lever to
return to low-beam headlamps.

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
174 Lighting
The exterior lamps and dome lamp
remain on for a set amount of time,
then automatically turn off.
The exterior lamps turn off
immediately by turning the exterior
lamp control off.
This feature can be changed. See
Vehicle Personalization0157.
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.Normally, these actions occur in
steps or levels, without being
noticeable. In rare cases at the
highest levels of corrective action,
this action may be noticeable to the
driver. If so, a DIC message might
be displayed and it is recommended
that the driver reduce the electrical
loads as much as possible.
Battery Power Protection
This feature shuts off the dome and
reading lamps, if they are left on for
more than 10 minutes after the
ignition is turned off. The cargo
lamp shuts off after 20 minutes. This
prevents the battery from
running down.
Exterior Lighting Battery
Saver
The exterior lamps turn off about
10 minutes after the ignition is
turned off, if the parking lamps or
headlamps have been manually left
on. This protects against draining
the battery. To restart the 10-minute

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 193
Warning (Continued)
cause a rollover. You could be
injured or killed. Do not drive on
steep hills.
Before driving on a hill, assess the
steepness, traction, and
obstructions. If the terrain ahead
cannot be seen, get out of the
vehicle and walk the hill before
driving further.
When driving on hills:
. Use a low gear and keep a firm
grip on the steering wheel.
. Maintain a slow speed.
. When possible, drive straight up
or down the hill.
. Slow down when approaching
the top of the hill.
. Use headlamps even during the
day to make the vehicle more
visible.
{Warning
Driving to the top of a hill at high
speed can cause a crash. There
could be a drop-off, embankment,
cliff, or even another vehicle. You
could be seriously injured or
killed. As you near the top of a
hill, slow down and stay alert.
. Never go downhill forward or
backward with either the
transmission or transfer case in
N (Neutral). The brakes could
overheat and you could lose
control.
{Warning
If the vehicle has the two-speed
automatic transfer case, shifting
the transfer case to N (Neutral)
can cause your vehicle to roll
even if the transmission is in
P (Park). This is because the
N (Neutral) position on the
(Continued)
Warning (Continued)
transfer case overrides the
transmission. You or someone
else could be injured. If leaving
the vehicle, set the parking brake
and shift the transmission to
P (Park). Shift the transfer case to
any position but N (Neutral).
. When driving down a hill, keep
the vehicle headed straight
down. Use a low gear because
the engine will work with the
brakes to slow the vehicle and
help keep the vehicle under
control.
{Warning
Heavy braking when going down
a hill can cause your brakes to
overheat and fade. This could
cause loss of control and you or
others could be injured or killed.
Apply the brakes lightly when
(Continued)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 199
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.
If the Vehicle Is Stuck
Slowly and cautiously spin the
wheels to free the vehicle when
stuck in sand, mud, ice, or snow.
See“Rocking the Vehicle to Get It
Out” later in this section.
The Traction Control/Electronic
Stability Control can often help to
free a stuck vehicle. See Traction
Control/Electronic Stability Control
0 235. If TC/ESC cannot free the
vehicle, see “Rocking the Vehicle to
Get it Out” following.
{Warning
If the vehicle's tires spin at high
speed, they can explode, and you
or others could be injured. The
vehicle can overheat, causing an
engine compartment fire or other
damage. Spin the wheels as little
as possible and avoid going
above 56 km/h (35 mph).
For information about using tire
chains on the vehicle, see Tire
Chains 0404.
Rocking the Vehicle to Get
It Out
Caution
Do not hold the steering wheel at
full rotation for more than
15 seconds and/or at an elevated
RPM. Damage may occur to the
power steering system and there
may be loss of power steering
assist. Turn the steering wheel left and
right to clear the area around the
front wheels. Then make sure the
wheels are pointed straight ahead.
For four-wheel-drive vehicles, shift
into Four-Wheel Drive High. Turn
the TCS off. Shift back and forth
between R (Reverse) and a forward
gear, spinning the wheels as little as
possible. To prevent transmission
wear, wait until the wheels stop
spinning before shifting gears.
Slowly spinning the wheels in the
forward and reverse directions
causes a rocking motion that could
free the vehicle. If that does not get
the vehicle out after a few tries, it
might need to be towed out. See
Towing the Vehicle
0424. Recovery
hooks can be used, if the vehicle
has them.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
246 Driving and Operating
used, ACC can be turned back on.
Disabling the TCS or StabiliTrak/
ESC system will disengage and
prevent engagement of ACC.
ACC can reduce the need for you to
frequently brake and accelerate,
especially when used on
expressways, freeways, and
interstate highways. When used on
other roads, you may need to take
over the control of braking or
acceleration more often.
{Warning
ACC has limited braking ability
and may not have time to slow
the vehicle down enough to avoid
a collision with another vehicle
you are following. This can occur
when vehicles suddenly slow or
stop ahead, or enter your lane.
Also see“Alerting the Driver” later
in this section. Complete attention
is always required while driving
and you should be ready to take
action and apply the brakes. See
Defensive Driving 0187.
{Warning
ACC will not detect or brake for
children, pedestrians, animals,
or other objects.
Do not use ACC when:
. On winding and hilly roads
or when the camera sensor
is blocked by snow, ice,
or dirt. The system may not
detect a vehicle ahead.
Keep the windshield and
headlamps clean.
. When visibility is poor due
to rain, snow, fog, dirt,
insect residue, or dust;
when other foreign objects
obscure the camera’s view;
or when the vehicle in front
or oncoming traffic causes
additional environmental
obstructions, such as road
spray. ACC performance is
limited under these
conditions.
(Continued)
Warning (Continued)
.On slippery roads where
fast changes in tire traction
can cause excessive
wheel slip
. With extremely heavy cargo
loaded in the cargo area or
rear seat
. When towing a trailer