2020 GMC SIERRA roof

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Seats and Restraints 77
airbag causing the bag to break out
of the cover. The inflator, the airbag,
and related hardware are all part of
the airbag module.
For airbag locations, seeWhere Are
the Airbags? 074.
How Does an Airbag
Restrain?
In moderate to severe frontal or
near frontal collisions, even belted
occupants can contact the steering
wheel or the instrument panel. In
moderate to severe side collisions,
even belted occupants can contact
the inside of the vehicle.
Airbags supplement the protection
provided by seat belts by
distributing the force of the impact
more evenly over the
occupant's body.
Rollover capable roof-rail airbags
are designed to help contain the
head and chest of occupants in the
outboard seating positions in the
first and second rows. The rollover
capable roof-rail airbags are
designed to help reduce the risk of full or partial ejection in rollover
events, although no system can
prevent all such ejections.
But airbags would not help in many
types of collisions, primarily
because the occupant's motion is
not toward those airbags. See
When
Should an Airbag Inflate? 076.
Airbags should never be regarded
as anything more than a supplement
to seat belts.
What Will You See after
an Airbag Inflates?
After frontal and seat-mounted side
impact airbags inflate, they quickly
deflate, so quickly that some people
may not even realize the airbags
inflated. Roof-rail airbags may still
be at least partially inflated for some
time after they inflate. Some
components of the airbag module
may be hot for several minutes. For
location of the airbags, see Where
Are the Airbags? 074.
The parts of the airbag that come
into contact with you may be warm,
but not too hot to touch. There may be some smoke and dust coming
from the vents in the deflated
airbags. Airbag inflation does not
prevent the driver from seeing out of
the windshield or being able to steer
the vehicle, nor does it prevent
people from leaving the vehicle.
{Warning
When an airbag inflates, there
may be dust in the air. This dust
could cause breathing problems
for people with a history of
asthma or other breathing trouble.
To avoid this, everyone in the
vehicle should get out as soon as
it is safe to do so. If you have
breathing problems but cannot
get out of the vehicle after an
airbag inflates, then get fresh air
by opening a window or a door.
If you experience breathing
problems following an airbag
deployment, you should seek
medical attention.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
84 Seats and Restraints
of the seat fabric, could also
interfere with the operation of the
passenger sensing system. This
could either prevent proper
deployment of the passenger
airbag(s) or prevent the passenger
sensing system from properly
turning off the passenger airbag(s).
SeePassenger Sensing System
0 78.
If the vehicle has rollover roof-rail
airbags, see Different Size Tires
and Wheels 0401 for additional
important information.
If a snow plow is added to the
vehicle, the airbags should still work
properly. The airbag systems were
designed to work properly under a
wide range of conditions, including
snow plowing with vehicles that
have the optional snow plow prep
package (RPO VYU). Do not
change or defeat the snow plow's
“tripping mechanism.” If you do, it
can damage the snow plow and the
vehicle, and may cause an airbag
deployment. If the vehicle must be modified
because you have a disability and
have questions about whether the
modifications will affect the vehicle's
airbag system, or if you have
questions about whether the airbag
system will be affected if the vehicle
is modified for any other reason, call
Customer Assistance. See
Customer Assistance Offices
0465.
Airbag System Check
The airbag system does not need
regularly scheduled maintenance or
replacement. Make sure the airbag
readiness light is working. See
Airbag Readiness Light 0136.
Caution
If an airbag covering is damaged,
opened, or broken, the airbag
may not work properly. Do not
open or break the airbag
coverings. If there are any
opened or broken airbag
coverings, have the airbag
(Continued)
Caution (Continued)
covering and/or airbag module
replaced. For the location of the
airbags, seeWhere Are the
Airbags? 074. See your dealer
for service.
Replacing Airbag System
Parts after a Crash
{Warning
A crash can damage the airbag
systems in the vehicle.
A damaged airbag system may
not properly protect you and your
passenger(s) in a crash, resulting
in serious injury or even death. To
help make sure the airbag
systems are working properly
after a crash, have them
inspected and any necessary
replacements made as soon as
possible.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Instruments and Controls 121
depending on how long the
windshield washer had been
activated. SeeWasher Fluid0354
for information on filling the
windshield washer fluid reservoir.
Clear snow and ice from the wiper
blades before using them. If frozen
to the windshield, carefully loosen or
thaw them. Damaged blades should
be replaced. See Wiper Blade
Replacement 0364.
Heavy snow or ice can overload the
wiper motor.
{Warning
In freezing weather, do not use
the washer until the windshield is
warmed. Otherwise the washer
fluid can form ice on the
windshield, blocking your vision.
{Warning
Before driving the vehicle, always
clear snow and ice from the hood,
windshield, roof, and rear of the
vehicle, including all lamps and
windows. Reduced visibility from
snow and ice buildup could lead
to a crash.
Wipe Parking
If the ignition is turned off while the
wipers are on LO, HI, or
3, they
will immediately stop.
If the windshield wiper control is ON
then moved to OFF before the driver
door is opened or within 10 minutes,
the wipers will restart and move to
the base of the windshield.
If the ignition is turned off while the
wipers are performing wipes due to
windshield washing, the wipers
continue to run until they reach the
base of the windshield.
Compass
The vehicle may have a compass
display on the Driver Information
Center (DIC). The compass receives
its heading and other information
from the Global Positioning
System (GPS) antenna, Electronic
Stability Control (ESC), and vehicle
speed information.
The compass system is designed to
operate for a certain number of
miles or degrees of turn before
needing a signal from the GPS
satellites. When the compass
display shows CAL, drive the
vehicle for a short distance in an
open area where it can receive a
GPS signal. The compass system
will automatically determine when a
GPS signal is restored and provide
a heading again.
Clock
The time and date for the clock can
be set using the infotainment
system. See “Time/Date”in
“System” under“Settings” in the
infotainment manual.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
166 Lighting
For vehicles first sold in Canada, off
will only work when the vehicle is in
P (Park).
AUTO :Automatically turns on the
headlamps, parking lamps,
taillamps, instrument panel lights,
roof marker lamps (if equipped),
front/rear sidemarker lamps, and
license plate lamps.
;: Turns on the parking lamps
including all lamps, except the
headlamps and fog lamps,
if equipped.
2: Turns on the headlamps
together with the parking lamps,
taillamps, instrument panel lights,
roof marker lamps (if equipped),
front/rear sidemarker lamps, and
license plate lamps.
For some trim levels and series of
trucks first sold in Canada, the
headlamps may turn on with the
parking lamps."
When the headlamps are turned on
while the vehicle is on, the
headlamps turn off automatically
10 minutes after the ignition is
turned off. When the headlamps are turned on while the vehicle is off,
the headlamps will stay on for
10 minutes before turning off to
prevent the battery from being
drained. Turn the headlamp control
off and then back to the headlamp
on position to make the headlamps
stay on for an additional 10 minutes.
To keep the lamps on for more than
10 minutes, the ignition must be on
or in ACC/ACCESSORY.
K:
If equipped, turns on the task
lighting. See Task Lighting 0171.
IntelliBeam System
If equipped, this system turns the
vehicle's high-beam headlamps on
and off according to surrounding
traffic conditions.
The system turns the high-beam
headlamps on when it is dark
enough and there is no other traffic
present.
This light
bcomes on in the
instrument cluster when the
IntelliBeam system is enabled. Turning On and Enabling
IntelliBeam
To enable the IntelliBeam system,
press the button on the end of the
turn signal lever when the exterior
lamp control is in the AUTO or
2
position. The blue high-beam on
light appears on the instrument
cluster when the high beams are on.
Driving with IntelliBeam
The system only activates the high
beams when driving over 40 km/h
(25 mph).
There is a sensor near the top
center of the windshield that
automatically controls the system.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
192 Driving and Operating
To gain more ground clearance if
needed, it may be necessary to
remove the front fascia lower air
dam, if equipped. However, driving
without the air dam reduces fuel
economy.
Caution
Operating the vehicle for
extended periods without the front
fascia lower air dam installed can
cause improper airflow to the
engine. Reattach the front fascia
air dam after off-road driving.
Loading the Vehicle for
Off-Road Driving
{Warning
.Unsecured cargo on the
load floor can be tossed
about when driving over
rough terrain. You or your
(Continued)
Warning (Continued)
passengers can be struck
by flying objects. Secure the
cargo properly.
. Keep cargo in the cargo
area as far forward and as
low as possible. The
heaviest things should be
on the floor, forward of the
rear axle.
. Heavy loads on the roof
raise the vehicle's center of
gravity, making it more likely
to roll over. You can be
seriously or fatally injured if
the vehicle rolls over. Put
heavy loads inside the
cargo area, not on the roof.
For more information about loading
the vehicle, see Vehicle Load Limits
0 200 and
Tires 0379.
Environmental Concerns
.
Always use established trails,
roads, and areas that have been
set aside for public off-road
recreational driving and obey all
posted regulations.
. Do not damage shrubs, flowers,
trees, or grasses or disturb
wildlife.
. Do not park over things that
burn. See Parking over Things
That Burn 0219.
Driving on Hills
Driving safely on hills requires good
judgment and an understanding of
what the vehicle can and cannot do.
{Warning
Many hills are simply too steep
for any vehicle. Driving up hills
can cause the vehicle to stall.
Driving down hills can cause loss
of control. Driving across hills can
(Continued)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
216 Driving and Operating
3. Light-Duty only, remove theengine heater connector cover
by gently prying with a flat
blade tool.
4. Plug the heater cord into the connector in the front fascia.
5. Plug the cord into a grounded 110-volt AC outlet that is
protected by a ground fault
detection function.
{Warning
Improper use of the heater cord
or an extension cord can damage
the cord and may result in
overheating and fire.
. Plug the cord into a
three-prong electrical utility
receptacle that is protected
by a ground fault detection
function. An ungrounded
outlet could cause an
electric shock.
. Use a weatherproof,
heavy-duty, 15 amp-rated
extension cord if needed.
Failure to use the
recommended extension
cord in good operating
condition, or using a
damaged heater or
extension cord, could make
(Continued)
Warning (Continued)
it overheat and cause a fire,
property damage, electric
shock, and injury.
. Do not operate the vehicle
with the heater cord
permanently attached to the
vehicle. Possible heater
cord and thermostat
damage could occur.
. While in use, do not let the
heater cord touch vehicle
parts or sharp edges. Never
close the hood on the
heater cord.
. Before starting the vehicle,
unplug the cord, reattach
the cover to the plug, and
securely fasten the cord.
Keep the cord away from
any moving parts.
6. Before starting the engine, be sure to unplug and store
the cord.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 217
The length of time the heater should
remain plugged in depends on
several factors. Ask a dealer in the
area where you will be parking the
vehicle for the best advice on this.
Retained Accessory
Power (RAP)
When the ignition is turned from on
to off, the following features (if
equipped) will continue to function
for up to 10 minutes, or until the
driver door is opened. These
features will also work when the
ignition is in RUN or ACC/
ACCESSORY:
.Infotainment System
. Power Windows (during RAP
this functionality will be lost
when any door is opened)
. Sunroof (during RAP this
functionality will be lost when
any door is opened)
. Auxiliary Power Outlet
. Audio System
. OnStar System
Shifting Into Park
{Warning
It can be dangerous to get out of
the vehicle if the shift lever is not
fully in P (Park) with the parking
brake firmly set. The vehicle can
roll. If you have left the engine
running, the vehicle can move
suddenly. You or others could be
injured. To be sure the vehicle will
not move, even when you are on
fairly level ground, use the steps
that follow. With four-wheel drive,
if the transfer case is in
N (Neutral), the vehicle will be
free to roll, even if the shift lever
is in P (Park). Be sure the transfer
case is in a drive gear. If towing a
trailer, see Driving Characteristics
and Towing Tips 0287.
1. Hold the brake pedal down, then set the parking brake. See
Electric Parking Brake 0233. 2. Move the shift lever into the
P (Park) position by pulling the
shift lever toward you and
moving it up as far as it will go.
3. Be sure the transfer case (if equipped) is in a drive
gear –not in N (Neutral).
4. Turn the ignition off. For Key Access, push the ignition key
in, towards the steering column
and then turn the ignition off.
5. For Key Access, remove the key and take it with you. If you
can leave the vehicle with the
ignition key in your hand, the
vehicle is in P (Park).
For Keyless Access, take the
Remote Keyless Entry (RKE)
transmitter with you.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 255
Lighting Conditions Affecting ACC
The ACC front camera can be
affected by poor lighting conditions,
and ACC may have limited
performance when:
.There are changes in brightness,
such as entering and exiting
tunnels, bridges, and
overpasses.
. Low sun angles cause the
camera to not detect objects,
or it is more difficult to detect
objects in the same traffic lane.
. Lighting is poor in the evening or
early morning
. There are multiple changes in
brightness or shadows along the
vehicle roadway.
. In a tunnel without the
headlamps on, or in a tunnel
when there is a vehicle in front
that does not have its
taillamps on. .
Subjected to strong light from
opposing lane traffic in the front
of the vehicle, such as
high-beam headlamps from
oncoming traffic.
Accessory Installations and
Vehicle Modifications
Do not install or place any object
around the front camera windshield
area that would obstruct the front
camera view.
Do not install objects on top of the
vehicle that overhang and obstruct
the front camera, such as a canoe,
kayak, or other items that can be
transported on the vehicle roof.
Do not modify the hood, headlamps,
or fog lamps, as this may limit the
camera’s ability to detect an object.
Cleaning the Sensing System
The camera sensor on the
windshield behind the rearview
mirror can become blocked by
snow, ice, dirt, mud, or debris. This
area needs to be cleaned for ACC
to operate properly. The vehicle headlamps may need to
be cleaned due to dirt, snow, or ice.
Objects that are not illuminated
correctly may be difficult to detect.
If ACC will not operate, regular
cruise control may be available. See
“Switching Between ACC and
Regular Cruise Control”
previously
in this section. Always consider
driving conditions before using
either cruise control system.
For cleaning instructions, see
“Washing the Vehicle” under
Exterior Care 0429.