2004 GMC YUKON XL DENALI sensor

When Should an Air Bag In¯ate?
Frontal Air Bags
The driver's and right front passenger's frontal air bags
are designed to in¯ate in moderate to severe frontal
or near-frontal crashes. But they are designed to in¯ate
only if the impact speed is above the system's
designed ªthreshold level.º
In addition, your vehicle has ªdual stageº frontal air
bags, which adjust the amount of restraint according to
crash severity. For moderate frontal impacts, these
air bags in¯ate at a level less than full deployment. For
more severe frontal impacts, full deployment occurs.
If the front of your vehicle goes straight into a wall that
doesn't move or deform, the threshold level for the
reduced deployment is about 10 to 16 mph
(16 to 25 km/h), and the threshold level for a full
deployment is about 20 to 25 mph (32 to 40 km/h).
The threshold level can vary, however, with speci®c
vehicle design, so that it can be somewhat above
or below this range.
If your vehicle strikes something that will move or
deform, such as a parked car, the threshold level will be
higher. The driver's and right front passenger's frontal
air bags are not designed to in¯ate in rollovers, rear
impacts, or in many side impacts because in¯ation
would not help the occupant.
Seat Position Sensors
Vehicles with dual stage air bags are also equipped with
special sensors which enable the sensing system to
monitor the position of both the driver and passenger
front seats. The seat position sensor provides
information which is used to determine if the air bags
should deploy at a reduced level or at full depoyment.
Side Impact Air Bags
Your vehicle may or may not have a side impact air
bag. SeeAir Bag Systems on page 1-72. Side impact air
bags are designed to in¯ate in moderate to severe
side crashes. A side impact air bag will in¯ate if
the crash severity is above the system's designed
ªthreshold level.º The threshold level can vary with
speci®c vehicle design. Side impact air bags are
not designed to in¯ate in frontal or near-frontal impacts,
rollovers or rear impacts, because in¯ation would not
help the occupant. A side impact air bag will only deploy
on the side of the vehicle that is struck.
Air Bag Systems
In any particular crash, no one can say whether an air
bag should have in¯ated simply because of the damage
to a vehicle or because of what the repair costs were.
For frontal air bags, in¯ation is determined by the angle
of the impact and how quickly the vehicle slows down
1-77

In many crashes severe enough to in¯ate an air bag,
windshields are broken by vehicle deformation.
Additional windshield breakage may also occur from the
right front passenger air bag.
·Air bags are designed to in¯ate only once. After an
air bag in¯ates, you'll need some new parts for
your air bag system. If you don't get them, the air
bag system won't be there to help protect you
in another crash. A new system will include air bag
modules and possibly other parts. The service
manual for your vehicle covers the need to replace
other parts.
·Your vehicle is equipped with electronic frontal
sensors which help the sensing system distinguish
between a moderate and a more severe frontal
impact. Your vehicle is also equipped with a crash
sensing and diagnostic module, which records
information about the frontal air bag system. The
module records information about the readiness of
the system and when the system commands air
bag in¯ation. It records the status of the driver's
safety belt usage in a crash in which the air
bag deploys or a crash in which the air bag nearly
deploys. The module also records speed, engine
rpm, brake and throttle data.
·Let only quali®ed technicians work on your air bag
systems. Improper service can mean that an air
bag system won't work properly. See your dealer for
service.
Notice:If you damage the covering for the driver's
or the right front passenger's air bag, or the air
bag covering on the driver's and right front
passenger's seatback, the bag may not work
properly. You may have to replace the air bag
module in the steering wheel, both the air bag
module and the instrument panel for the right front
passenger's air bag, or both the air bag module
and seatback for the driver's and right front
passenger's side impact air bag. Do not open or
break the air bag coverings.
1-80

Passenger Sensing System
If your rearview mirror has one of the indicators pictured
in the following illustrations, your vehicle has a
passenger sensing system. The indicator will be visible
when you turn your ignition key to START or RUN.
The words ON and OFF or the symbol for on and off,
will be visible on the rearview mirror during the system
check. When the system check is complete, either
the word ON or the word OFF, or the symbol for on or
the symbol for off will be visible. See
Passenger Air
Bag Status Indicator on page 3-34. If your rearview
mirror does not have either of the indicators pictured,
then your vehicle does not have the passenger sensing
system.The passenger sensing system will turn off the right
front passenger's frontal air bag under certain
conditions. The driver's air bag and the side air bags
are not part of the passenger sensing system.
The passenger sensing system works with sensors that
are part of the right front passenger's seat and safety
belt. The sensors are designed to detect the presence of
a properly-seated occupant and determine if the
passenger's frontal air bag should be enabled
(may in¯ate) or not.
Accident statistics show that children are safer if they
are restrained in the rear rather than the front seat.
General Motors recommends that child restraints
be secured in a rear seat, including an infant riding in a
rear-facing infant seat, a child riding in a forward-facing
child seat and an older child riding in a booster seat. Passenger Air Bag Status Indicator ± United States
Passenger Air Bag
Status Indicator
± Canada
1-81

Servicing Your Air Bag-Equipped
Vehicle
Air bags affect how your vehicle should be serviced.
There air bag system parts in several places around
your vehicle. You don't want the system to in¯ate while
someone is working on your vehicle. Your dealer
and the service manual have information about servicing
your vehicle and the air bag system. To purchase a
service manual, see
Service Publications Ordering
Information on page 7-11.
{CAUTION:
For up to 10 seconds after the ignition key is
turned off and the battery is disconnected, an
air bag can still in¯ate during improper
service. You can be injured if you are close to
an air bag when it in¯ates. Avoid yellow
connectors. They are probably part of the air
bag system. Be sure to follow proper service
procedures, and make sure the person
performing work for you is quali®ed to do so.
Air bag systems do not need regular maintenance.
Adding Equipment to Your Air
Bag-Equipped Vehicle
Q:Is there anything I might add to the front or
sides of the vehicle that could keep the air
bags from working properly?
A:Yes. If you add things that change your vehicle's
frame, bumper system, front end or side sheet
metal or height, they may keep the air bag system
from working properly. Also, the air bag system
may not work properly if you relocate any of the air
bag sensors. If you have any questions about
this, you should contact Customer Assistance
before you modify your vehicle. The phone
numbers and addresses for Customer Assistance
are in Step Two of the Customer Satisfaction
Procedure in this manual. See
Customer
Satisfaction Procedure on page 7-2
.
1-85

Automatic Headlamp System
When it is dark enough outside and the headlamp
switch is in AUTO, your automatic headlamp system will
turn on your headlamps at the normal brightness
along with other lamps such as the taillamps,
sidemarker, parking lamps, roof marker lamps and the
instrument panel lights. The radio lights will also be dim.
To turn off the automatic headlamp system, turn the
exterior lamps switch to the off position and then
release.
Your vehicle has a light sensor located on the top of the
instrument panel. Be sure it is not covered, or the
system will be on whenever the ignition is on.
The system may also turn on your headlamps when
driving through a parking garage, heavy overcast
weather or a tunnel. This is normal.
There is a delay in the transition between the daytime
and nighttime operation of the Daytime Running
Lamps (DRL) and the automatic headlamp systems so
that driving under bridges or bright overhead street
lights does not affect the system. The DRL and
automatic headlamp system will only be affected when
the light sensor sees a change in lighting lasting
longer than the delay.If you start your vehicle in a dark garage, the automatic
headlamp system will come on immediately. Once
you leave the garage, it will take approximately
one minute for the automatic headlamp system to
change to DRL if it is light outside. During that delay,
your instrument panel cluster may not be as bright
as usual. Make sure your instrument panel brightness
control is in the full bright position. See ªInstrument
Panel Brightnessº under
Interior Lamps on page 3-17.
Lamps On Reminder
If a door is open, a reminder chime will sound when
your headlamps or parking lamps are manually turned
on and your key is out of the ignition. To turn off
the chime, turn the headlamp switch to off or AUTO and
then back on. In the automatic mode, the headlamps
turn off once the ignition is in LOCK and the headlamps
on at exit delay ends (if enabled in the DIC).
3-15

Daytime Running Lamps
Daytime Running Lamps (DRL) can make it easier for
others to see the front of your vehicle during the
day. DRL can be helpful in many different driving
conditions, but they can be especially helpful in the short
periods after dawn and before sunset. Fully functional
daytime running lamps are required on all vehicles
®rst sold in Canada.
The DRL system will come on when the following
conditions are met:
·The ignition is on,
·the exterior lamps control is in AUTO,
·the transmission is not in PARK (P), and
·the light sensor determines it is daytime.
When the DRL are on, only your DRL lamps will be on.
The taillamps, sidemarker and other lamps won't be
on. The instrument panel won't be lit up either.
When it begins to get dark, the automatic headlamp
system will switch from DRL to the headlamps.
As with any vehicle, you should turn on the regular
headlamp system when you need it.
Fog Lamps
Use the fog lamps for better vision in foggy or misty
conditions. Your parking lamps and/or low-beam
headlamps must be on for your fog lamps to work.
The fog lamp button is
located on the left side of
your instrument panel.
Press the button to turn the fog lamps on while the
headlamps or parking lamps are on. Press the button
again to turn them off. An indicator light will glow
near the button when the fog lamps are on.
Remember, fog lamps alone will not give off as much
light as your headlamps. Never use your fog lamps
in the dark without turning on the headlamps.
The fog lamps will go off whenever your high-beam
headlamps come on. When the high beams go off, the
fog lamps will come on again.
3-16

Turn the knob counterclockwise or clockwise to lower or
increase the cabin temperature. The display will show
the temperature setting decreasing or increasing and an
arrow pointing to the passenger will be displayed
under and to the right of the temperature setting.
The passenger's temperature setting can be set to
match the driver's temperature setting by pressing and
holding the AUTO button for four seconds. Both the
driver and passenger arrows will be displayed.
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 driver's set temperature, delivery
mode and fan speed. Press the AUTO button again
within ®ve seconds to display the passenger's set
temperature.
If the driver and passenger's temperature settings
are not the same, the opposite side temperature
setting will be displayed for an additional ®ve
seconds. To make the passenger's temperature the
same as the driver's press and hold the AUTO
button for about four 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
40ÉF (4ÉC). The air inlet will normally be set to
outside air. If it's hot outside, the air inlet may
automatically switch to recirculate inside air to help
quickly cool down your vehicle. The light on the
button will illuminate in recirculation.
2. Set the driver's and passenger's temperature.
To ®nd your comfort setting, start with a 74ÉF (23ÉC)
temperature setting and allow about 20 minutes
for the system to regulate. Turn the driver's or
passenger's side temperature knob to adjust the
temperature setting as necessary. If you choose the
temperature setting of 60ÉF (15ÉC) the system
will remain at the maximum cooling setting. If you
choose the temperature setting of 90ÉF (32ÉC)
the system will remain at the maximum heat setting.
Choosing either maximum setting will not cause
the vehicle to heat or cool any faster.
Be careful not to cover the sensor located on the
top of the instrument panel near the windshield. This
sensor regulates air temperature based on sun
load, and also turns on your headlamps.
3-21

Speedometer and Odometer
Your speedometer lets you see your speed in both
miles per hour (mph) and kilometers per hour (km/h).
Your vehicle's odometer works together with the
driver information center. You can set a personal trip
and business trip odometer. See ªTrip Informationº under
DIC Operation and Displays on page 3-46.
The odometer mileage can be checked without the
vehicle running. Simply press the trip stem on the
instrument panel cluster.
If your vehicle ever needs a new odometer installed, the
new one will be set to the correct mileage total of the
old odometer.
Tachometer
Your tachometer displays the engine speed in
revolutions per minute (rpm).
Notice:If you operate the engine with the
tachometer in the shaded warning area, your vehicle
could be damaged, and the damages would not
be covered by your warranty. Do not operate
the engine with the tachometer in the shaded
warning area.
Safety Belt Reminder Light
When the key is turned to RUN or START, a chime will
come on for several seconds to remind people to
fasten their safety belts, unless the driver's safety belt is
already buckled.
The safety belt light will
also come on and stay on
for several seconds, then it
will ¯ash for several more.
If the driver's belt is already buckled, neither the chime
nor the light will come on.
Air Bag Readiness Light
There is an air bag readiness light on the instrument
panel, which shows the air bag symbol. The system
checks the air bag's electrical system for malfunctions.
The light tells you if there is an electrical problem.
The system check includes the air bag sensors, the air
bag modules, the wiring and the crash sensing and
diagnostic module. For more information on the air bag
system, see
Air Bag Systems on page 1-72.
3-32