2021 GMC YUKON ac drain

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
36 Keys, Doors, and Windows
.Press or pullC(2) again to stop at the
desired location.
Sunroof Vent Operation:
.Press and releaseE(3) to vent the
sunroof.
.Pull and releaseE(3) to close the
sunroof vent.
Automatic Reversal System
The sunroof and power sunshade,
if equipped, have an automatic reversal
system that is only active when the sunroof
and power sunshade are operated in
express-close mode.
If an object is in the path while
express-closing, the reversal system will
detect an object, stop, and open the sunroof
or power sunshade slightly.
If this condition occurs, attempt to remove
the object, then pull and release the switch
to express close. If the reversal occurs
multiple times, the DIC message OPEN THEN
CLOSE SUNROOF will display, and express is
disabled. To operate sunroof while express is
disabled, the switch must be either pressed
or pulled and held.
Dirt and debris may collect on the sunroof
seal or in the track. This could cause an
issue with sunroof operation or noise.
It could also plug the water drainage
system. Periodically open the sunroof and
remove any obstacles or loose debris. Wipe
the sunroof seal and roof sealing area using
a clean cloth, mild soap, and water. Do not
remove grease from the sunroof.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
100 Instruments and Controls
signal. The compass system will
automatically determine when a GPS signal
is restored and provide a heading again.
Clock
Set the time and date using the
infotainment system. See "Time / Date"
underSettings 0187.
Power Outlets
Accessory power outlets can be used to plug
in electrical equipment, such as a cell phone
or MP3 player.
The vehicle has one 12 Volt accessory power
outlet under the climate control system and
one 110/120 Volt Alternating Current outlet
on the rear of the center console.
Lift the cover to access and replace when
not in use.
12 Volt Power Outlet
Caution
Leaving electrical equipment plugged in
for an extended period of time while the
vehicle is off will drain the battery.
Always unplug electrical equipment when
not in use and do not plug in equipment
that exceeds the maximum 15 amp
rating.
Certain power accessory plugs may not be
compatible with the accessory power outlet
and could overload vehicle or adapter fuses.
If a problem is experienced, see your dealer. When adding electrical equipment, be sure
to follow the proper installation instructions
included with the equipment. See
Add-On
Electrical Equipment 0306.
Caution
Hanging heavy equipment from the
power outlet can cause damage not
covered by the vehicle warranty. The
power outlets are designed for accessory
power plugs only, such as cell phone
charge cords.
Power Outlet 110/120 Volt Alternating
Current
If equipped, the vehicle has two alternating
current power outlets. One on the back of
the center console and one in the rear of
the vehicle.

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
134 Lighting
Lighting
Exterior Lighting
Exterior Lamp Controls . . . . . . . . . . . . . . . . 134
Exterior Lamps Off Reminder . . . . . . . . . . 136
Headlamp High/Low-Beam Changer . . . 136
Flash-to-Pass . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
Daytime Running Lamps (DRL) . . . . . . . . . 136
Automatic Headlamp System . . . . . . . . . . 136
Hazard Warning Flashers . . . . . . . . . . . . . . 137
Turn and Lane-Change Signals . . . . . . . . . 138
Fog Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
Interior Lighting
Instrument Panel IlluminationControl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Dome Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Reading Lamps . . . . . . . . . . . . . . . . . . . . . . . . 139
Lighting Features
Entry Lighting . . . . . . . . . . . . . . . . . . . . . . . . . 140
Exit Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Battery Load Management . . . . . . . . . . . . 140
Battery Power Protection . . . . . . . . . . . . . . 141
Exterior Lighting Battery Saver . . . . . . . . . 141
Exterior Lighting
Exterior Lamp Controls
The exterior lamp control is on the
instrument panel to the left of the steering
wheel.
There are four positions:
O: Turns off the automatic headlamps and
Daytime Running Lamps (DRL). Turn the
headlamp control to
Oagain to turn the
automatic headlamps or DRL back on.
For vehicles first sold in Canada, the off
position will only work when the vehicle is
shifted into P (Park). AUTO :
Automatically turns on the
headlamps, parking lamps, taillamps,
instrument panel lights, roof marker lamps
(if equipped), and license plate lamps.
;: Turns on the parking lamps including
all lamps, except the headlamps.
2: Turns on the headlamps with the
parking lamps and instrument panel lights.
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.
IntelliBeam System
If equipped, this system turns the vehicle's
high-beam headlamps on and off according
to surrounding traffic conditions.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
Lighting 141
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 when the ignition is off. This will
keep 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 timer, turn
the exterior lamp control to the
Oposition
and then back to the
;or2position.
To keep the lamps on for more than
10 minutes, the ignition must be on or in
ACC/ACCESSORY.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
228 Driving and Operating
Service Mode
This power mode is available for service and
diagnostics, and to verify the proper
operation of the malfunction indicator lamp
as may be required for emission inspection
purposes. With the vehicle off, and the
brake pedal not applied, pressing and
holding the button for more than
five seconds will place the vehicle in Service
Mode. The instruments and audio systems
will operate as they do when the ignition is
on, but the vehicle will not be able to be
driven. The engine will not start in Service
Mode. Press the button again to turn the
ignition off.
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.
SeeAdd-On Electrical Equipment 0306. Shift the vehicle into P (Park) or N (Neutral).
To restart the engine when the vehicle is
already moving, use N (Neutral) only.
Caution
Do not try to shift to P (Park) if the
vehicle is moving. If you do, you could
damage the transmission. Shift to P (Park)
only when the vehicle is stopped.
Starting Procedure
1. The remote key must be in the vehicle.
Press ENGINE START/STOP with the brake
pedal applied. When the engine begins
cranking, let go of the button.
The idle speed will go down as the
engine gets warm. Do not race the
engine immediately after starting it.
Operate the engine and transmission
gently to allow the oil to warm up and
lubricate all moving parts.
When the low fuel warning light is on
and the FUEL LEVEL LOW message is
displayed in the Driver Information
Center (DIC), press the ENGINE START/
STOP position to continue engine
cranking.
Caution
Cranking the engine for long periods of
time, by trying to start the engine
immediately after cranking has ended,
can overheat and damage the cranking
motor, and drain the battery. Wait at
least 15 seconds between each try, to let
the cranking motor cool down.
2. If the engine does not start after five to 10 seconds, especially in very cold
weather (below −18 °C or 0 °F), it could
be flooded with too much gasoline. Try
pushing the accelerator pedal all the way
to the floor and holding it there while
pressing ENGINE START/STOP for up to a
maximum of 15 seconds. Wait at least
15 seconds between each try, to allow
the cranking motor to cool down. When
the engine starts, let go of the button
and accelerator. If the vehicle starts
briefly but then stops again, do the
same thing. This clears the extra gasoline
from the engine. Do not race the engine
immediately after starting it. Operate
the engine and transmission gently until
the oil warms up and lubricates all
moving parts.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
240 Driving and Operating
The actual 4x4 shift request is only made
after the button is released. The 4x4 graphic
will remain flashing until the shift request
has completed.
A DIC message displays. Once the 4x4 shift
has completed, the DIC message disappears,
the 4x4 graphic stops flashing, and the
current setting is indicated.
Brakes
Electric Brake Boost
Vehicles equipped with electric brake boost
have hydraulic brake circuits that are
electronically controlled when the brake
pedal is applied during normal operation.
The system performs routine tests and turns
off within a few minutes after the vehicle is
turned off. Noise may be heard during this
time. If the brake pedal is pressed during
the tests or when the electric brake boost
system is off, a noticeable change in pedal
force and travel may be felt. This is normal.
Antilock Brake System (ABS)
The Antilock Brake System (ABS) helps
prevent a braking skid and maintain steering
while braking hard.
If there is a problem with ABS, this warning
light stays on. SeeAntilock Brake System
(ABS) Warning Light 0113.
ABS does not change the time needed to
get a foot on the brake pedal and does not
always decrease stopping distance. If you
get too close to the vehicle ahead, there will
not be enough time to apply the brakes if
that vehicle suddenly slows or stops. Always
leave enough room ahead to stop, even
with ABS.
Using ABS
Do not pump the brakes. Just hold the brake
pedal down firmly. Hearing and feeling ABS
operate is normal.
Braking in Emergencies
ABS allows steering and braking at the same
time. In many emergencies, steering can
help even more than braking.
Electric Parking Brake
The Electric Parking Brake (EPB) can always
be applied, even if the vehicle is off. In case
of insufficient electrical power, the EPB
cannot be applied or released. To prevent
draining the battery, avoid unnecessary
repeated cycles of the EPB.
The system has a red parking brake status
light and an amber service parking brake
warning light. See Electric Parking Brake
Light 0113 and
Service Electric Parking Brake Light 0113.
There are also parking brake-related Driver
Information Center (DIC) messages.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13690468) - 2021 - crc - 8/14/20
300 Driving and Operating
Vehicle
1. Transmission Fluid Temperature
2. Average Fuel Economy with TrailerProfile
Average Fuel Economy
Touch to view the average fuel economy of
the vehicle while the Trailer Profile is active.
Transmission Temperature
View the temperature of the transmission
fluid by looking at the graphic. The graphic
will indicate a dangerous level if the
temperature is at 130 °C–150 °C (270 °F–
300 °F).
Connections
1. Light Test Start Button
2. Trailer Electrical Diagnostics
Connections: OK
If a trailer connection is detected without
any faults, the view will display OK.
Trailer Connections Status
When a trailer is connected, the Trailering
App System detects the trailer connection
using the Stop/Turn Signal lighting circuits
and alerts the driver by requesting a trailer
profile setup through the Trailering App
System on the infotainment screen. The
Trailer Detection Alert setting must be
enabled for the alert to display when a trailer is connected. When a trailer is
connected and the ignition is off, the
Trailering App System will periodically pulse
the lighting circuits of the trailer to verify it
is still connected. The trailer lights may
periodically flash as a result of this trailer
connection detection. These flashes may be
more visible in dark ambient light
environments. The flashing or flickering
lights are a normal condition and the
Trailering App System has built-in
protections to prevent the battery from
draining. When Theft Alert is also enabled
the frequency and pattern of this flashing
will change.
Connection Problem
If any of the trailer connections are lost, a
message about the connection issue will
appear on the Driver Information Center
(DIC). The infotainment display will also
show the connection issue in the Connection
Status view.
If a trailer connection is not detected, the
Trailering App will not display the
Connection Status screen.