light GMC YUKON XL DENALI 2007 Repair Manual

H(Vent):This setting will deliver air to the
instrument panel outlets.
)(Bi-Level):This mode directs half of the air
to the instrument panel outlets and to the oor
outlets. The ow can be divided between vent and
oor outlets depending upon where the knob is
placed between the settings. A little air is directed
towards the windshield and side window outlets.
Cooler air is directed to the upper outlets and
warmer air to the oor outlets.
6(Floor):This mode directs most of the air to
the oor outlets, with some of the air directed
to the windshield, side window outlets, and
second row oor outlets. In this mode, the system
will automatically select outside air.
-(Defog):See “Defogging and Defrosting” later
in this section.
@(Recirculation):Press this button to turn
the recirculation mode on. When the button
is pressed, an indicator light will come on.
This mode keeps outside air from entering the
vehicle. It can be used to reduce outside air and
prevent odors from entering your vehicle.
Recirculation may also help cool the air inside your
vehicle more quickly once the temperature inside
the vehicle is less than the outside temperature.
The recirculation mode cannot be used with oor,
defrost, or defogging modes. If you try to select
recirculation in one of those modes, the indicator
will ash three times and turn off. The air
conditioning compressor will also come 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.
Recirculation mode can be turned off by pressing
the button again, or turning off the engine.
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Air Conditioning
#
(Air Conditioning):Press this button to turn
the air conditioning (A/C) compressor on and
off. When air conditioning is selected, an indicator
light will come on to let you know that the air
conditioning has been activated.
Pressing this button when the outside temperature
is too cool for air conditioning will make the air
conditioning indicator ash three times and
then turn off to let you know the air conditioning
mode is not available. 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 will turn off
to let you know 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 your vehicle to cool down. It also
helps the system to operate more efficiently.
The air conditioning system removes moisture from
the air, so you may sometimes notice a small
amount of water dripping underneath your vehicle
while idling or after turning off the engine. This
is normal.
Sensors
The solar sensor, located in the defrost grille in
the middle of the instrument panel, monitors
the solar radiation. Do not cover the solar sensor
or the system will not work properly.
219

Warning Lights, Gages, and
Indicators
This part describes the warning lights and gages
on your vehicle. The pictures will help you
locate them.
Warning lights and gages can signal that
something is wrong before it becomes serious
enough to cause an expensive repair or
replacement. Paying attention to your warning
lights and gages could also save you or others
from injury.
Warning lights come on when there may be or
is a problem with one of your vehicle’s functions.
As you will see in the details on the next few
pages, some warning lights come on briey when
you start the engine just to let you know they
are working. If you are familiar with this section,
you should not be alarmed when this happens.Gages can indicate when there may be or is a
problem with one of your vehicle’s functions.
Often gages and warning lights work together
to let you know when there is a problem with your
vehicle.
When one of the warning lights comes on and
stays on when you are driving, or when one of
the gages shows there may be a problem, check
the section that tells you what to do about it.
Please follow this manual’s advice. Waiting to do
repairs can be costly – and even dangerous.
So please get to know your warning lights and
gages. They are a big help.
Your vehicle also has a Driver Information Center
(DIC) that works along with warning lights and
gages. SeeDIC Warnings and Messages
on page 252.
225

Safety Belt Reminder Light
When the key is turned to RUN or START, a chime
will be provided for several seconds to remind
people to buckle their safety belts. The driver safety
belt light will also be provided and stay on for
several seconds, then it will ash for several more.
You should buckle your seat belt.
This chime and light will
be repeated if the driver
remains unbuckled
and the vehicle
is in motion.
If the driver’s belt is buckled, neither the chime nor
the light will come on.
SeePassenger Sensing System on page 101for
more information.
Passenger Safety Belt Reminder
Light
Several seconds after the key is turned to RUN or
START, a chime will sound for several seconds to
remind the front passenger to buckle their safety
belt. This would only occur if the passenger airbag
is enabled. SeePassenger Sensing System on
page 101for more information. The passenger
safety belt light will also come on and stay on for
several seconds, then it will ash for several more.
This chime and light will
be repeated if the
passenger remains
unbuckled and
the vehicle is in motion.
If the passenger’s safety belt is buckled, neither
the chime nor the light will come on.
228

Airbag Readiness Light
There is an airbag readiness light on the
instrument panel, which shows the airbag symbol.
The system checks the airbag’s electrical
system for malfunctions. The light tells you if there
is an electrical problem. The system check
includes the airbag sensors, the airbag modules,
the wiring and the crash sensing and diagnostic
module. For more information on the airbag
system, seeAirbag System on page 90.
This light will come on
when you start your
vehicle, and it will ash
for a few seconds.
Then the light should go
out. This means the
system is ready.
If the airbag readiness light stays on after you
start the vehicle or comes on when you are driving,
your airbag system may not work properly.
Have your vehicle serviced right away.{CAUTION:
If the airbag readiness light stays on after
you start your vehicle, it means the airbag
system may not be working properly. The
airbags in your vehicle may not inate in
a crash, or they could even inate without
a crash. To help avoid injury to yourself
or others, have your vehicle serviced right
away if the airbag readiness light stays on
after you start your vehicle.
The airbag readiness light should ash for a few
seconds when you turn the ignition key to RUN.
If the light doesn’t come on then, have it xed so it
will be ready to warn you if there is a problem.
229

Passenger Airbag Status Indicator
Your vehicle has the passenger sensing system.
Your overhead console has a passenger airbag
status indicator.
When the ignition key is turned to RUN or START,
the passenger airbag status indicator will light
ON and OFF, or the symbol for on and off,
for several seconds as a system check. Then,
after several more seconds, the status indicator
will light either ON or OFF, or either the on
or off symbol to let you know the status of the
right front passenger’s frontal airbag.If the word ON or the on symbol is lit on the
passenger airbag status indicator, it means that
the right front passenger’s frontal airbag is enabled
(may inate).
{CAUTION:
If the on indicator comes on when you have
a rear-facing child restraint installed in the
right front passenger’s seat, it means that
the passenger sensing system has not
turned off the passenger’s frontal airbag.
A child in a rear-facing child restraint can
be seriously injured or killed if the right
front passenger’s airbag inates. This is
because the back of the rear-facing child
restraint would be very close to the
inating airbag. Do not use a rear-facing
child restraint in the right front passenger’s
seat if the airbag is turned on.
Passenger Airbag
Status
Indicator – United
StatesPassenger Airbag
Status
Indicator – Canada
230

Your vehicle has a rear seat that will accommodate
a rear-facing child restraint. A label on your sun
visor says, “Never put a rear-facing child seat
in the front.” This is because the risk to the
rear-facing child is so great, if the airbag deploys.
{CAUTION:
Even though the passenger sensing
system is designed to turn off the
passenger’s frontal airbag if the system
detects a rear-facing child restraint, no
system is failsafe, and no one can
guarantee that an airbag will not deploy
under some unusual circumstance, even
though it is turned off. We recommend
that rear-facing child restraints be secured
in the rear seat, even if the airbag is off.If the word OFF or the off symbol is lit on the
airbag status indicator, it means that the
passenger sensing system has turned off the right
front passenger’s frontal airbag. SeePassenger
Sensing System on page 101for more on
this, including important safety information.
If, after several seconds, all status indicator lights
remain on, or if there are no lights at all, there
may be a problem with the lights or the passenger
sensing system. See your dealer for service.
{CAUTION:
If the off indicator and the airbag
readiness light ever come on together, it
means that something may be wrong with
the airbag system. If this ever happens,
have the vehicle serviced promptly,
because an adult-size person sitting in the
right front passenger seat may not have
the protection of the frontal airbag. See
Airbag Readiness Light on page 229.
231

Charging System Light
The charging system
light will come on briey
when you turn on the
ignition, but the
engine is not running,
as a check to show you
it is working.
It should go out once the engine is running. If it
stays on, or comes on while you are driving,
you may have a problem with the charging system.
It could indicate that you have problems with a
generator drive belt, or another electrical problem.
Have it checked right away. Driving while this
light is on could drain your battery.
When this light comes on the DIC will also display
the battery not charging message. SeeDIC
Warnings and Messages on page 252.
If you must drive a short distance with the light on,
be certain to turn off all your accessories, such
as the radio and air conditioner.
Voltmeter Gage
When your engine is not
running, but the ignition
is in RUN, this gage
shows your battery’s
state of charge in
DC volts.
When the engine is running, the gage shows the
condition of the charging system. The gage
may transition from a higher to lower or a lower to
higher reading, this is normal. Readings between
the low and high warning zones indicate the
normal operating range.
232

Readings in the low warning zone may occur
when a large number of electrical accessories are
operating in the vehicle and the engine is left at
an idle for an extended period. This condition
is normal since the charging system is not able to
provide full power at engine idle. As engine
speeds are increased, this condition should correct
itself as higher engine speeds allow the charging
system to create maximum power.
You can only drive for a short time with the
reading in either warning zone. If you must drive,
turn off all unnecessary accessories.
Readings in either warning zone indicate a
possible problem in the electrical system. Have
the vehicle serviced as soon as possible.Brake System Warning Light
With the ignition on, the brake system warning
light will come on when you set the parking brake.
If you try to drive with the parking brake engaged,
a chime will sound when the vehicle speed is
greater than 3 mph (5 km/h).
Your vehicle’s hydraulic brake system is divided
into two parts. If one part is not working, the other
part can still work and stop you. For good
braking, though, you need both parts working well.
If the warning light comes on and a chime
sounds there could be a brake problem. Have
your brake system inspected right away.
This light may also come on due to low brake
uid. SeeBrakes on page 459for more
information.
233

This light should come on briey when you turn
the ignition key to RUN. If it does not come
on then, have it xed so it will be ready to warn
you if there’s a problem.
If the light comes on while you are driving, pull off
the road and stop carefully. You may notice
that the pedal is harder to push or may go closer
to the oor. It may take longer to stop. If the
light is still on, have the vehicle towed for service.
SeeTowing Your Vehicle on page 398.
{CAUTION:
Your brake system may not be working
properly if the brake system warning light
is on. Driving with the brake system
warning light on can lead to an accident.
If the light is still on after you have pulled
off the road and stopped carefully, have
the vehicle towed for service.
Anti-Lock Brake System Warning
Light
With the anti-lock brake
system, this light will
come on when you start
your engine and may
stay on for several
seconds.
United StatesCanada
234