2012 GMC YUKON air conditioning

Black plate (4,1)GMC Yukon/Yukon XL Owner Manual - 2012
8-4 Climate Controls
Dual Automatic Climate Control System
The heating, cooling, and ventilation in the vehicle can be controlled with
this system. The vehicle also has a flow-through ventilation system
described later in this section.
If the vehicle is a hybrid, see the hybrid supplement for more information.
A. Fan Control
B. AUTO (Automatic Operation)
C. Defrost
D. Recirculation
E. REAR (Rear Climate Control)F. Air Delivery Mode Control
G. Driver Temperature Control
H. Display
I. Power Button
J. Rear Window DefoggerK. Air Conditioning
L. PASS
M. Passenger Temperature Control
O(On/Off):
Press to turn the
climate control system on or off.
Outside air still enters the vehicle,
and is directed to the floor. This
direction can be changed by
pressing the mode button.
Recirculation can be selected once
you have selected vent or bi-level
mode. The temperature can also be
adjusted using either temperature
button. If the air delivery mode or
temperature settings are adjusted
with the system off, the display
illuminates briefly to show the
settings and then returns to off. The
system can be turned back on by
pressing either
O,D,C,#, the
defrost or the AUTO button.

Black plate (5,1)GMC Yukon/Yukon XL Owner Manual - 2012
Climate Controls 8-5
Driver and Passenger Side
Temperature Control
The driver and passenger side
temperature buttons are used to
adjust the temperature of the air
coming through the system on the
driver or passenger side of the
vehicle. The temperature can be
adjusted even if the system is
turned off. This is possible since
outside air always flows through the
system as the vehicle is moving
forward unless it is set to
recirculation mode. See
“Recirculation”later in this section.
Press the + or −buttons to increase
or decrease the cabin temperature.
The driver side or passenger side
temperature display shows the
temperature setting decreasing or
increasing. The passenger temperature setting
can be set to match the driver
temperature setting by pressing the
PASS button and turning off the
PASS indicator.
When in defrost mode the
passenger temperature setting
cannot be changed.
Automatic Operation
AUTO (Automatic):
When
automatic operation is active the
system will control the inside
temperature, the air delivery, and
the fan speed.
Use the steps below to place the
entire system in automatic mode:
1. Press the AUTO button.
When AUTO is selected, the
display will change to show the
current temperature(s) and
AUTO will be lit on the display.
The current delivery mode and
fan speed will also be displayed
for approximately 5 seconds. When AUTO is selected, the air
conditioning operation and air
inlet will be automatically
controlled. The air conditioning
compressor will run when the
outside temperature is over
about 4°C (40°F). The air inlet
will normally be set to outside
air. If it is hot outside, the air
inlet may automatically switch to
recirculate inside air to help
quickly cool down the vehicle.
The light on the button comes on
in recirculation.
2. Set the driver and passenger temperature.
To find your comfort setting, start
with a 23°C (74°F) temperature
setting and allow about
20 minutes for the system to
regulate. Use the driver or
passenger temperature buttons
to adjust the temperature setting
as necessary. If a temperature
setting of 15°C (60°F) is chosen,

Black plate (7,1)GMC Yukon/Yukon XL Owner Manual - 2012
Climate Controls 8-7
-(Defog):This mode clears the
windows of fog or moisture. Air is
directed to the windshield, floor
outlets, and side window vents. In
this mode, the system turns off
recirculation and runs the air
conditioning compressor unless the
outside temperature is close to
freezing. The recirculation mode
cannot be selected while in the
defog mode.
0(Defrost): This mode removes
fog or frost from the windshield
more quickly. Air is directed to the
windshield and side window vents,
with some directed to the floor
vents. In this mode, the system
automatically forces outside air into
the vehicle and runs the air
conditioning compressor unless the
outside temperature is close to
freezing. The recirculation mode
cannot be selected while in the
defrost mode. The passenger temperature control
cannot be activated while in defrost
mode. If the PASS button is
pressed, the button indicator flashes
three times and will not work. If the
passenger temperature buttons are
adjusted, the driver temperature
indicator changes. The passenger
temperature will not be displayed.
If vent, bi-level, or floor mode is
selected again, the climate control
system displays the previous
temperature settings.
Do not drive the vehicle until all the
windows are clear.
#(Air Conditioning):
Press to
turn the air conditioning (A/C)
compressor on and off. An indicator
light comes on to show that the air
conditioning is on. If this button is pressed when the air
conditioning compressor is
unavailable, the indicator flashes
three times and then turns off. If the
air conditioning is on and the
outside temperature drops below a
temperature which is too cool for air
conditioning to be effective, the air
conditioning light turns off to show
that the air conditioning mode has
been canceled.
On hot days, open the windows long
enough to let hot inside air escape.
This helps to reduce the time it
takes for the vehicle to cool down.
It also helps the system to operate
more efficiently.
The air conditioning system
removes moisture from the air, so a
small amount of water might drip
under the vehicle while idling or
after turning off the engine. This is
normal.

Black plate (8,1)GMC Yukon/Yukon XL Owner Manual - 2012
8-8 Climate Controls
@(Recirculation):Press to turn
the recirculation mode on or off. An
indicator light comes on to show
that the recirculation is on.
This mode recirculates and helps to
quickly cool the air inside the
vehicle. It can be used to help
prevent outside air and odors from
entering the vehicle.
The recirculation mode cannot be
used with floor, defog, or defrost
modes. If recirculation is selected
with one of those modes, the
indicator light flashes three times
and then turns off. The air
conditioning compressor also comes
on when this mode is activated.
While in recirculation mode the
windows may fog when the weather
is cold and damp. To clear the fog,
select either the defog or defrost
mode and increase the fan speed.
The recirculation mode can also be
turned off by turning off the ignition. PASS:
Press to set the passenger
temperature setting to match the
driver temperature setting. The
PASS indicator will turn off. When
the passenger temperature setting
is set different than the driver
setting, the indicator on the PASS
button illuminates and both the
driver side and passenger side
temperature displays are shown.
REAR: For vehicles with the rear
heat and air conditioning controls.
Press to turn the rear climate control
system on or off. See Rear Climate
Control System (Rear Climate
Control Only) on page 8‑10 orRear
Climate Control System (Rear
Climate with Rear Seat Audio) on
page 8‑11.
Rear Window Defogger
The rear window defogger uses a
warming grid to remove fog from the
rear window.
1(Rear Window Defogger):
Press to turn the rear window
defogger on or off. It automatically
turns off several minutes after it has
been activated. The defogger can
also be turned off by turning off the
engine. Do not drive the vehicle until
all the windows are clear.
Notice: Do not use a razor blade
or sharp object to clear the inside
rear window. Do not adhere
anything to the defogger grid
lines in the rear glass. These
actions may damage the rear
defogger. Repairs would not be
covered by your warranty.
Heated Mirrors: Press
1to help
clear fog or frost from the surface of
the outside mirror. See Power
Mirrors on page 2‑17.

Black plate (11,1)GMC Yukon/Yukon XL Owner Manual - 2012
Climate Controls 8-11
Air Delivery Mode Control:Turn
clockwise or counterclockwise to
change the direction of the airflow.
H(Vent): Air is directed through
the headliner outlets.
)(Bi-Level): Air is directed
through the floor and headliner
outlets. The rear system floor
outlets are located directly behind
the second row seats. The flow can
be divided between vent and floor
outlets depending upon where the
knob is placed between the settings.
6(Floor): Air is directed to the
floor outlets. The rear system floor
outlets are located directly behind
the second row seats.
Rear Climate Control System
(Rear Climate with Rear Seat Audio)
For vehicles with the rear heat and air conditioning controls, they are
integrated with the rear seat audio controls located in the center console.
The system can be controlled from the front controls as well as the rear
controls.
Rear Climate Control with Rear Seat Audio Controls
A. Fan Control
B. Air Delivery Mode Control
C. Temperature Control REAR:
Press the REAR button on
the front climate control system to
turn the rear climate control system
on or off. An indicator comes on
when the rear system is on.

Black plate (13,1)GMC Yukon/Yukon XL Owner Manual - 2012
Climate Controls 8-13
Air Vents
Use the air outlets located in the
center and on the side of the
instrument panel to direct the
airflow.
Operation Tips
.Keep the hood and front air
inlets free of ice, snow, or any
other obstruction (such as
leaves). The heater and
defroster will work far better,
reducing the chance of fogging
the inside of the windows.
.When you enter a vehicle in cold
weather, press the fan up button
to the maximum fan level before
driving. This helps clear the
intake ducts of snow and
moisture, and reduces the
chance of fogging the inside of
the window.
.Keep the air path under the front
seats clear of objects. This helps
air to circulate throughout the
vehicle.
.Adding outside equipment to the
front of the vehicle, such as
hood-air deflectors, may affect
the performance of the heating
and air conditioning system.
Check with your dealer before
adding equipment to the outside
of the vehicle.

Black plate (23,1)GMC Yukon/Yukon XL Owner Manual - 2012
Vehicle Care 10-23
.Idles for long periods in traffic.
.Tows a trailer. SeeTrailer
Towing on page 9‑72.
If the overheat warning is displayed
with no sign of steam:
1. Turn the air conditioning off.
2. Turn the heater on to the highest temperature and to the highest
fan speed. Open the windows as
necessary.
3. In heavy traffic, let the engine idle in N (Neutral) while stopped.
If it is safe to do so, pull off the
road, shift to P (Park) or
N (Neutral) and let the
engine idle.
If the temperature overheat gauge
is no longer in the overheat zone
or an overheat warning no longer
displays, the vehicle can be driven.
Continue to drive the vehicle slowly
for about 10 minutes. Keep a safe
vehicle distance from the vehicle in
front. If the warning does not come
back on, continue to drive normally. If the warning continues, pull
over, stop, and park the vehicle
right away.
If there is no sign of steam, idle
the engine for three minutes
while parked. If the warning is still
displayed, turn off the engine until it
cools down. Also, see
“Overheated
Engine Protection Operating Mode”
later in this section.
Overheated Engine
Protection
Operating Mode
If an overheated engine condition
exists and the ENGINE POWER IS
REDUCED message is displayed,
an overheat protection mode which
alternates firing groups of cylinders
helps prevent engine damage. In
this mode, a loss in power and
engine performance will be noticed.
This operating mode allows the
vehicle to be driven to a safe place
in an emergency. Driving extended distances and/or towing a trailer in
the overheat protection mode
should be avoided.
Notice:
After driving in the
overheated engine protection
operating mode, to avoid engine
damage, allow the engine to cool
before attempting any repair.
The engine oil will be severely
degraded. Repair the cause of
coolant loss, change the oil and
reset the oil life system. See
Engine Oil on page 10‑8.
Engine Fan
If the vehicle has a clutched engine
cooling fan, when the clutch is
engaged, the fan spins faster to
provide more air to cool the engine.
In most everyday driving conditions,
the fan is spinning slower and the
clutch is not fully engaged.
This improves fuel economy and
reduces fan noise. Under heavy
vehicle loading, trailer towing, and/
or high outside temperatures, the
fan speed increases as the clutch

Black plate (24,1)GMC Yukon/Yukon XL Owner Manual - 2012
10-24 Vehicle Care
more fully engages, so an increase
in fan noise may be heard. This is
normal and should not be mistaken
as the transmission slipping or
making extra shifts. It is merely the
cooling system functioning properly.
The fan will slow down when
additional cooling is not required
and the clutch disengages.
This fan noise may also be heard
when starting the engine. It will go
away as the fan clutch partially
disengages.
If the vehicle has electric cooling
fans, the fans may be heard
spinning at low speed during most
everyday driving. The fans may turn
off if no cooling is required. Under
heavy vehicle loading, trailer
towing, high outside temperatures,
or operation of the air conditioning
system, the fans may change to
high speed and an increase in fan
noise may be heard. This is normal
and indicates that the cooling
system is functioning properly.The fans will change to low speed
when additional cooling is no longer
required.
Power Steering Fluid
If the vehicle is a hybrid, see the
hybrid supplement for more
information.
See
Engine Compartment Overview
on page 10‑6 for reservoir location.
When to Check Power Steering
Fluid
It is not necessary to regularly
check power steering fluid unless
there is a leak suspected in the
system or an unusual noise is
heard. A fluid loss in this system
could indicate a problem. Have the
system inspected and repaired.
How to Check Power Steering
Fluid
Notice:Extremely small amounts
of contamination can cause
steering system damage and
cause it to not work properly. Do
not allow contaminants to contact
the fluid side of the reservoir
cap/dipstick or from entering the
reservoir.
To check the power steering fluid:
1. Turn the key off and let the engine compartment cool down.
2. Wipe the cap and the top of the reservoir clean.
3. Unscrew the cap and wipe the dipstick with a clean rag.
4. Replace the cap and completely tighten it.
5. Remove the cap again and look at the fluid level on the dipstick.