heating GMC YUKON XL 2010 User Guide

The interior temperature sensors located in the
headliner above the driver side seat and if equipped, in
the headliner above the second row seats measure the
temperature of the air inside the vehicle.
There is also an exterior temperature sensor located
behind the front grille. This sensor reads the outside air
temperature and helps maintain the temperature inside
the vehicle. Any cover on the front of the vehicle could
cause a false reading in the displayed temperature.
The climate control system uses the information from
these sensors to maintain your comfort setting by
adjusting the outlet temperature, fan speed, and
the air delivery mode. The system may also supply
cooler air to the side of the vehicle facing the sun.
The recirculation mode will also be used as needed
to maintain cool outlet temperatures.
Outlet Adjustment
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.
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Rear Air Conditioning and Heating
System
For vehicles with this system, the rear controls are three
knobs located in the headliner. The system can also be
controlled with the front controls.
A. Fan Control
B. Temperature Control
C. Air Delivery Mode 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. See Climate Control System
on page 4‑18orDual Automatic Climate Control System
on page 4‑20.
The rear system can also be turned off by turning the
rear fan knob to the
9position.
Mimic Mode: This mode matches the rear climate
control to the front climate control airflow settings.
It comes on when REAR is pressed the first time.
Independent Mode: This mode directs rear seating
airflow according to the settings of the rear controls.
It comes on when any rear control is adjusted.
Temperature Control: Turn clockwise or
counterclockwise to increase or decrease the
airflow temperature into the passenger area.
Fan Control: Turn clockwise or counterclockwise to
increase or decrease the fan speed.
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.
4-27

Rear Air Conditioning and Heating
System and Electronic Climate
Controls
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.
The rear climate control system can also be turned
off by pressing and holding the
Cbutton. To turn the
system on from the rear seats, press any rear climate
control button, except the
Cbutton.
Mimic Mode: This mode matches the rear climate
control to the front climate control airflow settings.
It comes on when REAR is pressed the first time.
Independent Mode: This mode directs rear seating
airflow according to the settings of the rear controls.
To turn the system on from the rear, press any rear
climate control button, except the
Cbutton.
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StabiliTrak®Indicator Light
For vehicles with the
StabiliTrak®system, this
light comes on briefly
while starting the engine.
If it does not, have the vehicle serviced by your dealer.
If the system is working normally the indicator light then
goes off.
If the light comes on and stays on while driving, there
could be a problem with the StabiliTrak
®system and the
vehicle might need service. When this warning light is
on, the StabiliTrak
®system is off and does not limit
wheel spin.
The light flashes if the system is active and is working
to assist the driver with directional control of the vehicle
in difficult driving conditions.
See StabiliTrak
®Systemon page 5‑6for more
information.
Engine Coolant Temperature Gauge
United StatesCanada
This gauge shows the engine coolant temperature.
It also provides an indicator of how hard the vehicle is
working. During a majority of the operation, the gauge
reads 210°F (100°C) or less. If you are pulling a load
or going up hills, it is normal for the temperature to
fluctuate and approach the 250°F (122°C) mark. If the
gauge reaches the 260°F (125°C) mark, it indicates that
the cooling system is working beyond its capacity.
See Engine Overheating on page 6‑36.
If the vehicle is a Two-mode Hybrid, see the Two-mode
Hybrid manual for more information.
4-38

ENGINE OVERHEATED IDLE ENGINE
Notice:If you drive your vehicle while the engine is
overheating, severe engine damage may occur. If an
overheat warning appears on the instrument panel
cluster and/or DIC, stop the vehicle as soon as
possible. See Engine Overheating
on page 6‑36for
more information.
This message displays when the engine coolant
temperature is too hot. Stop and allow the vehicle
to idle until it cools down. See Engine Coolant
Temperature Gauge on page 4‑38.
See Overheated Engine Protection Operating Mode
on
page 6‑39for information on driving to a safe place in
an emergency.
ENGINE OVERHEATED STOP ENGINE
Notice: If you drive your vehicle while the engine is
overheating, severe engine damage may occur. If an
overheat warning appears on the instrument panel
cluster and/or DIC, stop the vehicle as soon as
possible. See Engine Overheating
on page 6‑36for
more information.
This message displays and a chime sounds if the
engine cooling system reaches unsafe temperatures for
operation. Stop and turn off the vehicle as soon as it is
safe to do so to avoid severe damage. This message
clears when the engine has cooled to a safe operating
temperature.
ENGINE POWER IS REDUCED
This message displays and a chime sounds when the
cooling system temperature gets too hot and the engine
further enters the engine coolant protection mode.
See Engine Overheating
on page 6‑36for further
information.
This message also displays when the vehicle's engine
power is reduced. Reduced engine power can affect the
vehicle's ability to accelerate. If this message is on, but
there is no reduction in performance, proceed to your
destination. The performance may be reduced the next
time the vehicle is driven. The vehicle may be driven
at a reduced speed while this message is on, but
acceleration and speed may be reduced. Anytime this
message stays on, the vehicle should be taken to your
dealer for service as soon as possible.
FUEL LEVEL LOW
This message displays and a chime sounds if the fuel
level is low. Refuel as soon as possible. See Fuel
Gauge
on page 4‑46and Fuelon page 6‑6for
more information.
HOOD OPEN
This message displays and a chime sounds if the hood
is not fully closed. Stop and turn off the vehicle, check
the hood for obstructions, and close the hood again.
Check to see if the message still appears on the DIC.
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There are several conditions that can cause this
message to appear.
.One condition is overheating, which could occur if
StabiliTrak activates continuously for an extended
period of time.
.The message also displays if the brake system
warning light is on. SeeBrake System Warning
Light on page 4‑36.
.The message could display if the stability system
takes longer than usual to complete its diagnostic
checks due to driving conditions.
.The message displays if an engine or vehicle
related problem has been detected and the vehicle
needs service. See your dealer.
.The message also displays if the vehicle is shifted
into 4LO (Two Speed Transfer Case Only).
The message turns off as soon as the conditions that
caused the message to be displayed are no longer
present.
TIGHTEN GAS CAP
This message may display along with the check engine
light on the instrument panel cluster if the vehicle's fuel
cap is not tightened properly. See Malfunction Indicator
Lamp
on page 4‑39. Reinstall the fuel cap fully.
See Filling the Tankon page 6‑11. The diagnostic
system can determine if the fuel cap has been left off or
improperly installed. A loose or missing fuel cap allows
fuel to evaporate into the atmosphere. A few driving
trips with the cap properly installed should turn this light
and message off.
TIRE LEARNING ACTIVE
On vehicles with the Tire Pressure Monitor System
(TPMS), this message displays when the TPMS is
re-learning the tire positions on your vehicle. The tire
positions must be re-learned after rotating the tires or
after replacing a tire or sensor. See Tire Inspection and
Rotation
on page 6‑78, Tire Pressure Monitor Systemon page 6‑73, and Inflation - Tire Pressureon
page 6‑72for more information.
4-69

TRANSMISSION HOT IDLE ENGINE
Notice:If you drive your vehicle while the
transmission fluid is overheating and the
transmission temperature warning is displayed
on the instrument panel cluster and/or DIC, you
can damage the transmission. This could lead to
costly repairs that would not be covered by your
warranty. Do not drive your vehicle with overheated
transmission fluid or while the transmission
temperature warning is displayed.
This message displays along with a sound if the
transmission fluid in the vehicle gets hot. Driving with
the transmission fluid temperature high can cause
damage to the vehicle. Stop the vehicle and let it idle to
allow the transmission to cool. This message clears and
the chime stops when the fluid temperature reaches a
safe level.
TURN SIGNAL ON
This message displays and a chime sounds if a turn
signal is left on for 3/4 of a mile (1.2 km). Move the turn
signal/multifunction lever to the off position.
WASHER FLUID LOW ADD FLUID
This message displays when the windshield washer
fluid is low. Fill the windshield washer fluid reservoir as
soon as possible. See Engine Compartment Overview
on page 6‑16for the location of the windshield washer
fluid reservoir. Also, see Windshield Washer Fluidon
page 6‑41for more information.
4-71

Backing Up
Hold the bottom of the steering wheel with one hand.
Then, to move the trailer to the left, move that hand to
the left. To move the trailer to the right, move your hand
to the right. Always back up slowly and, if possible,
have someone guide you.
Making Turns
Notice:Making very sharp turns while trailering
could cause the trailer to come in contact with the
vehicle. The vehicle could be damaged. Avoid
making very sharp turns while trailering.
When turning with a trailer, make wider turns than
normal. Do this so the trailer will not strike soft
shoulders, curbs, road signs, trees or other objects.
Avoid jerky or sudden maneuvers. Signal well in
advance.
If the trailer turn signal bulbs burn out, the arrows on the
instrument panel will still flash for turns. It is important to
check occasionally to be sure the trailer bulbs are still
working.
Driving On Grades
Reduce speed and shift to a lower gear beforestarting
down a long or steep downgrade. If the transmission
is not shifted down, the brakes might get hot and no
longer work well.
Vehicles can tow in D (Drive). Shift the transmission to
a lower gear if the transmission shifts too often under
heavy loads and/or hilly conditions.
The tow/haul mode may be used if the transmission
shifts too often. See Tow/Haul Mode on page 3‑39.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a
lower temperature than at normal altitudes. If the engine
is turned off immediately after towing at high altitude on
steep uphill grades, the vehicle may show signs similar
to engine overheating. To avoid this, let the engine run
while parked, preferably on level ground, with the
automatic transmission in P (Park) for a few minutes
before turning the engine off. If the overheat warning
comes on, see Engine Overheating on page 6‑36.
5-65

Section 6 Service and Appearance Care
Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
Accessories and Modifications . . . . . . . . . . . . . . . . . . 6-4
California Proposition 65 Warning . . . . . . . . . . . . . . . 6-5
California Perchlorate Materials Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5
Doing Your Own Service Work . . . . . . . . . . . . . . . . . . 6-5
Adding Equipment to the Outside of the Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
Gasoline Octane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
Gasoline Specifications . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
California Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
Additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
Fuel E85 (85% Ethanol) . . . . . . . . . . . . . . . . . . . . . . . . . 6-9
Fuels in Foreign Countries . . . . . . . . . . . . . . . . . . . . . 6-10
Filling the Tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-11
Filling a Portable Fuel Container . . . . . . . . . . . . . . . 6-13
Checking Things Under the Hood . . . . . . . . . . . . . . .6-14
Hood Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14
Engine Compartment Overview . . . . . . . . . . . . . . . . 6-16
Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18
Engine Oil Life System . . . . . . . . . . . . . . . . . . . . . . . . 6-20
Engine Air Cleaner/Filter . . . . . . . . . . . . . . . . . . . . . . . 6-22
Automatic Transmission Fluid (4-Speed Transmission) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-24 Automatic Transmission Fluid (6-Speed
Transmission) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-27
Cooling System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-30
Engine Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-32
Engine Overheating . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-36
Overheated Engine Protection Operating Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-39
Engine Fan Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-39
Power Steering Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . 6-40
Windshield Washer Fluid . . . . . . . . . . . . . . . . . . . . . . 6-41
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-42
Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-45
Jump Starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-46
Rear Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-51
Four-Wheel Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-52
Front Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-53
Headlamp Aiming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-55
Bulb Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-58
Halogen Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-58
Taillamps, Turn Signal, Stoplamps and Back-up Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-58
License Plate Lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-60
Replacement Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-60
Windshield Wiper Blade Replacement . . . . . . . . . . .6-61
6-1

Automatic Transmission Fluid
(6-Speed Transmission)
When to Check and Change Automatic
Transmission Fluid
It is usually not necessary to check the transmission
fluid level. The only reason for fluid loss is a
transmission leak or overheating the transmission.
If you suspect a small leak, then use the following
checking procedures to check the fluid level. However,
if there is a large leak, then it may be necessary to have
the vehicle towed to a dealer service department and
have it repaired before driving the vehicle further.
Notice:Use of the incorrect automatic transmission
fluid may damage the vehicle, and the damages may
not be covered by the vehicle's warranty. Always
use the automatic transmission fluid listed in
Recommended Fluids and Lubricants on page 7‑11.
Change the fluid and filter at the intervals listed in the
Maintenance Schedule. See Scheduled Maintenance
on page 7‑3. Be sure to use the transmission fluid
listed in Recommended Fluids and Lubricantson
page 7‑11.
How to Check Automatic Transmission
Fluid
Notice: Too much or too little fluid can damage the
transmission. Too much can mean that some of the
fluid could come out and fall on hot engine parts or
exhaust system parts, starting a fire. Too little fluid
could cause the transmission to overheat. Be sure
to get an accurate reading if checking the
transmission fluid.
Before checking the fluid level, prepare the vehicle as
follows:
1. Start the engine and park the vehicle on a level surface. Keep the engine running.
2. Apply the parking brake and place the shift lever in P (Park).
3. With your foot on the brake pedal, move the shift lever through each gear range, pausing for about
three seconds in each range. Then, move the shift
lever back to P (Park).
6-27