
GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
46 Seats and Restraints
With the engine running, pressMorLto
heat the left or right outboard seat cushion.
An indicator on the rear climate control
display appears when this feature is on.
Press the button once for the highest
setting. With each press of the button, the
seat will change to the next lower setting,
and then to the off setting. The indicator
lights next to the buttons indicate three for
the highest setting and one for the lowest.
If the heated seats are on high for an
extended time, their level may automatically
be lowered.Second Row Seats
Rear Seat Adjustment
To adjust the seat position:
1. Remove objects on the floor in front of or on the second row seat, or in the seat
tracks on the floor.
2. Lift the lever below the seat cushion and slide the seat forward or backward.
Reclining Seatbacks
To recline the seatback:
1. Lift the lever on the outboard side ofthe seat.
2. Move the seatback to the desired position, and then release the lever to
lock the seatback in place.
3. Push and pull on the seatback to make sure it is locked.
To return the seatback to the upright
position:

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Instruments and Controls 111
Charging System Light
The charging system light comes on briefly
when the ignition is turned on, but the
engine is not running, as a check to show
the light is working. It should go out when
the engine is started.
If the light stays on, or comes on while
driving, there may be a problem with the
electrical charging system. Have it checked
by your dealer. Driving while this light is on
could drain the battery.
When this light comes on, or is flashing, the
Driver Information Center (DIC) also displays
a message.
If a short distance must be driven with the
light on, be sure to turn off all accessories,
such as the radio and air conditioner.
Malfunction Indicator Lamp
(Check Engine Light)
This light is part of the vehicle’s emission
control on-board diagnostic system. If this
light is on while the engine is running, a
malfunction has been detected and the
vehicle may require service. The light should
come on to show that it is working when
the ignition is in Service Mode. SeeIgnition
Positions 0226.
Malfunctions are often indicated by the
system before any problem is noticeable.
Being aware of the light and seeking service
promptly when it comes on may prevent
damage.
Caution
If the vehicle is driven continually with
this light on, the emission control system
may not work as well, the fuel economy
may be lower, and the vehicle may not
(Continued)
Caution (Continued)
run smoothly. This could lead to costly
repairs that might not be covered by the
vehicle warranty.
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 0309.
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.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
130 Instruments and Controls
Passive Door Lock
This allows passive locking to be turned on
or off and selects feedback. SeeRemote
Keyless Entry (RKE) System Operation 08.
Touch Off, On with Horn Chirp, or On.
Remote Left in Vehicle Alert
This feature sounds an alert when the
Remote Key is left in the vehicle.
Touch Off or On.
Remote Removed from Vehicle Alert
This feature beeps the horn 3 times when
exiting a running vehicle with the
Remote Key.
Touch Off or On.
Ride Height
Touch and the following may display:
.Automatic Entry/Egress
Automatic Entry/Egress
This feature specifies if the vehicle will
automatically lower to make it easier to
enter or exit the vehicle.
Touch Off or On.
Running Boards
Touch and the following may display:
.Automatic Running Boards
.Deploy Running Boards
Automatic Running Boards
This feature specifies the position and use of
the running boards. See Power Assist Steps
0 25.
Touch Off or On.
Deploy Running Boards
This feature moves the running boards to a
deployed position so they can be used with
the doors closed.
Touch Off or Deploy.
Seating Position
Touch and the following may display:
.Seat Entry Memory
.Seat Exit Memory
Seat Entry Memory
This feature automatically recalls the
previously stored 1 or 2 button positions
when the ignition is changed from off to on
or ACC/ACCESSORY. See Memory Seats041.
Touch Off or On. Seat Exit Memory
This feature automatically recalls the
previously stored exit button position when
the ignition is changed from on or ACC/
ACCESSORY to off and the driver door is
open. See
Memory Seats 041.
Touch Off or On.
Suspension
Touch and the following may display:
.Service Mode
.Alignment Mode
Service Mode
This feature disables the air suspension
system and is used to prevent unintended
raising or lowering of the suspension..
Touch Off or On.
Alignment Mode
This feature will optimize the vehicle height
to provide the most accurate wheel
alignment.
Touch Off or On.
Teen Driver
See “Teen Driver” underSettings 0187.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
206 Climate Controls
Manual Operation
Fan Control :Turn clockwise or
counterclockwise to increase or decrease the
fan speed. Press the knob to turn the fan
off. When off is selected, a small amount of
air may still come out of the outlets
depending on vehicle speed. If any buttons
are pressed or knobs are turned, the climate
control system will turn on and operate at
the current setting.
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. The driver
side or passenger side temperature display
shows the temperature setting increasing or
decreasing.
SYNC : Press to link the passenger and rear
temperature setting to the driver setting.
The SYNC indicator light will turn on. When
the passenger setting is adjusted, the SYNC
indicator light will turn off. Air Delivery Mode Control :
Press
z,Y,
or
[to change the direction of the
airflow. Any combination of the three
controls can be selected. 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.
To change the current mode, select one or
more of the following:
z: Air is directed to the windshield,
outboard a/c outlets, and side window
outlets.
Y: Air is directed to the a/c outlets.
[:Air is directed to the floor outlets,
with some air directed to the windshield,
outboard a/c outlets, and side window
outlets.
0MAX : Air is directed to the windshield
and the fan runs at a higher speed if not
already above a medium fan speed. This
mode overrides the previous mode selected
and clears fog or frost from the windshield
more quickly. When the control is pressed
again, the system returns to the previous
mode setting and fan speed. For best results, clear all snow and ice from
the windshield before defrosting.
@:
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.
Avoid using recirculation for long periods of
time in cold or damp conditions. Using
recirculation in cold or damp conditions can
result in window fogging.
A/C : Press to turn the air conditioning 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
1REAR : 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 engine is running. The defogger turns
off if the ignition is turned off or to ACC/
ACCESSORY.