2020 GMC SIERRA trailer

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
Introduction 7
16. Trailer Brake Control Panel (IfEquipped). See “Integrated
Trailer Brake Control System”
under Towing Equipment
0 296.
17. ENGINE START/STOP. See Ignition Positions (Keyless
Access) 0208 or
Ignition Positions (Key Access)
0 210.
18. Steering Wheel Controls (If Equipped). See the
infotainment manual.
Driver Information Center (DIC)
Controls. See Driver
Information Center (DIC) (Base
Level) 0148 or
Driver Information Center (DIC)
(Midlevel and Uplevel) 0149.
19. Horn 0120.
20. Hood Release. See Hood
0 330.
21. Steering Wheel Adjustment
0119 (Out of View).
22. Cruise Control 0243.
Adaptive Cruise Control (1500
Series) 0245 (If Equipped). Forward Collision Alert (FCA)
System
0268 (If Equipped).
23. Data Link Connector (DLC) (Out of View). See Malfunction
Indicator Lamp (Check Engine
Light) 0138.
24. Electric Parking Brake 0233.
25. Fog Lamps 0170 (If
Equipped).
Instrument Panel Illumination
Control 0172.
Exterior Cargo Lamps 0171.
Exterior Lamp Controls 0165.
Task Lighting 0171 (If
Equipped).

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Keys, Doors, and Windows 9
Keys, Doors, and
Windows
Keys and Locks
Keys (Key Access) . . . . . . . . . . . . . . 9
Keys (Keyless Access) . . . . . . . . 12
Remote Keyless Entry (RKE)System . . . . . . . . . . . . . . . . . . . . . . . 13
Remote Keyless Entry (RKE) System Operation (Key
Access) . . . . . . . . . . . . . . . . . . . . . . 13
Remote Keyless Entry (RKE) System Operation (Keyless
Access) . . . . . . . . . . . . . . . . . . . . . . 15
Remote Vehicle Start . . . . . . . . . . 24
Door Locks . . . . . . . . . . . . . . . . . . . . 25
Power Door Locks . . . . . . . . . . . . . 26
Delayed Locking . . . . . . . . . . . . . . . 26
Automatic Door Locks . . . . . . . . . 26
Lockout Protection . . . . . . . . . . . . . 27
Safety Locks . . . . . . . . . . . . . . . . . . . 27
Doors
Tailgate . . . . . . . . . . . . . . . . . . . . . . . . 28
Power Assist Steps . . . . . . . . . . . . 36
Vehicle Security
Vehicle Security . . . . . . . . . . . . . . . . 37
Vehicle Alarm System . . . . . . . . . 37 Steering Column Lock . . . . . . . . . 38
Immobilizer . . . . . . . . . . . . . . . . . . . . 39
Immobilizer Operation . . . . . . . . . 39
Exterior Mirrors
Convex Mirrors . . . . . . . . . . . . . . . . 40
Manual Mirrors . . . . . . . . . . . . . . . . . 41
Trailer-Tow Mirrors . . . . . . . . . . . . . 41
Power Mirrors . . . . . . . . . . . . . . . . . . 43
Folding Mirrors . . . . . . . . . . . . . . . . . 43
Heated Mirrors . . . . . . . . . . . . . . . . . 44
Automatic Dimming Mirror . . . . . 44
Blind Spot Mirrors . . . . . . . . . . . . . . 44
Reverse Tilt Mirrors . . . . . . . . . . . . 45
Interior Mirrors
Interior Rearview Mirrors . . . . . . . 46
Manual Rearview Mirror . . . . . . . . 46
Automatic Dimming Rearview
Mirror . . . . . . . . . . . . . . . . . . . . . . . . . 46
Rear Camera Mirror . . . . . . . . . . . . 46
Windows
Windows . . . . . . . . . . . . . . . . . . . . . . . 48
Manual Windows . . . . . . . . . . . . . . 49
Power Windows . . . . . . . . . . . . . . . 49
Rear Windows . . . . . . . . . . . . . . . . . 51
Sun Visors . . . . . . . . . . . . . . . . . . . . . 51
Roof
Sunroof . . . . . . . . . . . . . . . . . . . . . . . . 51
Keys and Locks
Keys (Key Access)
{Warning
Leaving children in a vehicle with
the ignition key is dangerous and
children or others could be
seriously injured or killed. They
could operate the power windows
or other controls or make the
vehicle move. The windows will
function with the keys in the
ignition, and children or others
could be caught in the path of a
closing window. Do not leave
children in a vehicle with the
ignition key.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Keys, Doors, and Windows 33
.Press5on the center stack.
. Press the lower touch pad on
the tailgate handle after
unlocking all doors. Use the top
of the tailgate to pull against if
assistance is required.
To close the primary tailgate, firmly
push it upward until it latches. Pull it
back to be sure it is latched
securely.To open the inner tailgate, press the
upper touch pad on the tailgate
handle after unlocking all doors. Pull
the top of the tailgate to open.
Caution
Do not open the inner tailgate
with the primary tailgate open if
there is a hitch ball or trailer
attached. This may damage the
tailgate.
To close the inner tailgate with the
primary tailgate closed, firmly push
or pull it upward until it latches. Pull
it back to be sure it is latched
securely.
To close the inner tailgate with the
primary tailgate open:
. Hold the primary tailgate and
firmly close the inner tailgate.
. Raise the inner tailgate so it
meets the primary tailgate and
close together at the same time.
When using the tailgate step as a
load stop, the load must be secured
as the load could shift. See Cargo
Tie-Downs 0116.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
40 Keys, Doors, and Windows
Transmitters to the Vehicle" under
Remote Keyless Entry (RKE)
System Operation (Key Access)
013 or
Remote Keyless Entry (RKE)
System Operation (Keyless Access)
0 15
Do not leave the transmitter or
device that disarms or deactivates
the vehicle theft system in the
vehicle.
When equipped with a key, if the
engine still does not start, and the
key appears to be undamaged, try
another ignition key. It may be
necessary to check the fuse. See
Fuses and Circuit Breakers 0370.
If the engine still does not start with
the other key, the vehicle needs
service. If the vehicle does start, the
first key may be faulty. See your
dealer. It is possible for the
immobilizer system to learn new or
replacement keys. Up to eight keys
can be programmed for the vehicle.
To program additional keys, see
Keys (Key Access) 09or
Keys (Keyless Access) 012. Do not leave the key or device that disarms
or deactivates the vehicle theft
system in the vehicle.
See your dealer to get a new key
blank cut exactly as the ignition key
that operates the system.Exterior Mirrors
Convex Mirrors
{Warning
A convex mirror can make things,
like other vehicles, look farther
away than they really are. If you
cut too sharply into the right lane,
you could hit a vehicle on the
right. Check the inside mirror or
glance over your shoulder before
changing lanes.
Standard Mirrors
The passenger side mirror is convex
shaped. A convex mirror's surface is
curved so more can be seen from
the driver seat.
Trailer-Tow Mirrors
The upper portion of both the driver
and passenger mirrors is flat.
The lower portion of both the driver
and passenger mirrors is convex.
A convex mirror ’s surface is curved

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Keys, Doors, and Windows 41
so more can be seen from the driver
seat. The lower portion is adjusted
manually.
Manual Mirrors
If equipped, adjust manual mirrors
by moving the mirror up and down
or left to right to see a little of the
side of the vehicle and to have a
clear view behind the vehicle.
Using hood-mounted air deflectors
and add-on convex mirror
attachments could decrease mirror
performance.
Trailer-Tow Mirrors
Extending Mirrors
Trailer tow mirrors can extend out
for better visibility when towing a
trailer.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
42 Keys, Doors, and Windows
Manual Extend :If equipped, grasp
the mirror housing firmly and pull
back in one motion, arching slightly
toward the rear of the vehicle.
To return the mirror to its original
position, reverse the motion.
Power Extend : If equipped, press
the power extend button to fully
extend the mirror. Press again to
retract.
Resetting the Power Extend
Mirrors
Reset the power extend mirrors if:
. The mirrors are accidentally
obstructed while extending/
retracting.
. The mirrors are accidentally
manually extended/retracted.
. The mirrors vibrate at normal
driving speeds. If a popping noise from the mirror is
heard, this sound is normal as the
manual detents are aligning after a
manual extend/retract operation has
occurred.
Auxiliary Cargo Mirror Lamps
If equipped, cargo mirror lamps face
rearward to provide more light on
the sides of the vehicle, if needed.
See
Exterior Cargo Lamps 0171.
Advanced Trailering Vision
System Side Cameras
If equipped, the Advanced Trailering
Vision System side cameras are on
the bottom of the outside mirrors.
See “Surround Vision (360
Degrees)” underAssistance
Systems for Parking or Backing
0 257.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Instruments and Controls 139
Caution
Modifications to the engine,
transmission, exhaust, intake,
or fuel system, or the use of
replacement tires that do not
meet the original tire
specifications, can cause this light
to come on. This could lead to
costly repairs not covered by the
vehicle warranty. This could also
affect the vehicle’s ability to pass
an Emissions Inspection/
Maintenance test. See
Accessories and Modifications
0329.
If the light is flashing : A
malfunction has been detected that
could damage the emission control
system and increase vehicle
emissions. Diagnosis and service
may be required.
To help prevent damage, reduce
vehicle speed and avoid hard
accelerations and uphill grades. If towing a trailer, reduce the
amount of cargo being hauled as
soon as possible.
If the light continues to flash, find a
safe place to park. Turn the vehicle
off and wait at least 10 seconds
before restarting the engine. If the
light is still flashing, follow the
previous guidelines and see your
dealer for service as soon as
possible.
If the light is on steady :
A
malfunction has been detected.
Diagnosis and service may be
required.
Check the following:
. If fuel has been added to the
vehicle using the capless funnel
adapter, make sure that it has
been removed. See “Filling the
Tank with a Portable Gas Can”
under Filling the Tank (Pickup
Model) 0283 or
Filling the Tank (Chassis Cab
Model) 0285. The diagnostic
system can detect if the adapter
has been left installed in the
vehicle, allowing fuel to evaporate into the atmosphere.
A few driving trips with the
adapter removed may turn off
the light.
. Poor fuel quality can cause
inefficient engine operation and
poor driveability, which may go
away once the engine is warmed
up. If this occurs, change the
fuel brand. It may require at
least one full tank of the proper
fuel to turn the light off. See
Recommended Fuel (Except
6.2L V8 Engine) 0280 or
Recommended Fuel (6.2L
V8 Engine) 0281.
If the light remains on, see your
dealer.
Emissions Inspection and
Maintenance Programs
If the vehicle requires an Emissions
Inspection/Maintenance test, the
test equipment will likely connect to
the vehicle's Data Link
Connector (DLC).

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
144 Instruments and Controls
dealer. If the system is working
normally, the indicator light then
turns off.
The traction off light comes on when
the Traction Control System (TCS)
has been turned off by pressing and
releasing the TCS/ESC button.
This light and the Electronic Stability
Control (ESC) OFF light come on
when ESC is turned off.
If the TCS is off, wheel spin is not
limited. Adjust driving accordingly.
SeeTraction Control/Electronic
Stability Control 0235.
Traction Control System
(TCS)/Electronic Stability
Control Light
If equipped, the Electronic Stability
Control (ESC) or TCS indicator/
warning light comes on briefly when
the engine is started.
If the light does not come on, have
the vehicle serviced by your dealer.
If the system is working normally,
the indicator light turns off.
If the light is on and not flashing, the
TCS, and potentially the ESC
system have been disabled.
If the indicator/warning light is on
and flashing, the TCS and/or the
ESC system is actively working.
See Traction Control/Electronic
Stability Control 0235.
Trailer Sway Control Light
(Uplevel Cluster)
This light will flash when Trailer
Sway Control is active. See Trailer
Sway Control (TSC) 0308.
Electronic Stability
Control (ESC) Off Light
This light comes on briefly while
starting the engine. If it does not,
have the vehicle serviced by your
dealer.
This light comes on when the ESC
system is turned off. If ESC is off,
the Traction Control System (TCS)
is also off.
If the ESC and TCS are off, the
system does not assist in controlling
the vehicle. Turn on the TCS and
the ESC systems and the warning
light turns off.
See Traction Control/Electronic
Stability Control 0235.