2004 GMC SIERRA DENALI sensor

Seat Position Sensors
Vehicle's 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.
What Makes an Air Bag In¯ate?
In an impact of sufficient severity, the air bag sensing
system detects that the vehicle is in a crash. The
sensing system triggers a release of gas from the
in¯ator, which in¯ates the air bag. The in¯ator, air bag,
and related hardware are all part of the air bag
modules inside the steering wheel and in the instrument
panel in front of the right front passenger.
How Does an Air Bag Restrain?
In moderate to severe frontal or near-frontal collisions,
even belted occupants can contact the steering wheel or
the instrument panel. Air bags supplement the
protection provided by safety belts. Air bags distribute
the force of the impact more evenly over the occupant's
upper body, stopping the occupant more gradually.But air bags would not help you in many types of
collisions, including rollovers, rear impacts and many
side impacts, primarily because an occupant's motion is
not toward those air bags. Air bags should never be
regarded as anything more than a supplement to safety
belts, and then only in moderate to severe frontal or
near-frontal collisions.
What Will You See After an Air Bag
In¯ates?
After an air bag in¯ates, it quickly de¯ates, so quickly
that some people may not even realize the air bag
in¯ated. Some components of the air bag module ± the
steering wheel hub for the driver's air bag, or the
instrument panel for the right front passenger's
bag ± will be hot for a short time. The parts of the bag
that come into contact with you may be warm, but
not too hot to touch. There will be some smoke and dust
coming from the vents in the de¯ated air bags. Air
bag in¯ation does not prevent the driver from seeing or
being able to steer the vehicle, nor does it stop
people from leaving the vehicle.
1-66

{CAUTION:
When an air bag in¯ates, there is dust in the
air. This dust could cause breathing problems
for people with a history of asthma or other
breathing trouble. To avoid this, everyone in
the vehicle should get out as soon as it is safe
to do so. If you have breathing problems but
can't get out of the vehicle after an air bag
in¯ates, then get fresh air by opening a
window or a door. If you experience breathing
problems following an air bag deployment, you
should seek medical attention.
In many crashes severe enough to in¯ate the 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
they in¯ate, you will need some new parts for
your air bag system. If you do not get them, the air
bag system will not be there to help protect you
in another crash. A new system will include air bagmodules 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 will not 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, the bag
may not work properly. You may have to replace the
air bag module in the steering wheel or both the
air bag module and the instrument panel for
the right front passenger's air bag. Do not open or
break the air bag coverings.
1-67

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 RUN or START.
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 3-33. If your rearview
mirror does not have either of the indicators pictured
below, 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 is not part of the
passenger sensing system. In addition to the passenger
sensing system, your vehicle also has an air bag off
switch located on the instrument panel.
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.
Passenger Air Bag Status Indicator ± United States
Passenger Air
Bag Status
Indicator-Canada
1-73

Servicing Your Air Bag-Equipped
Vehicle
Air bags affect how your vehicle should be serviced.
There are parts of the air bag system 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.
The air bag system does 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
.
1-78

Automatic Headlamp System
When it is dark enough outside, your automatic
headlamp system will turn on your headlamps at the
normal brightness along with other lamps such as
the taillamps, sidemarker, parking lamps and the
instrument panel lights. The radio lights will also be dim.
Your vehicle is equipped with a headlamp off delay,
which will keep the headlamps on for a short time after
the ignition is turned off. For more information see
DIC Operation and Displays on page 3-46.
Your vehicle has a light sensor located on the top of the
instrument panel in the defroster grille. 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 bright enough 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 Brightness Controlº under
Interior
Lamps on page 3-16.
To idle your vehicle with the automatic headlamp
system off, turn the control to the off position.
You may be able to turn off your automatic headlamp
system. See Daytime Running Lamps (DRL) later in this
section for more information.
Your headlamps will also stay on after you exit the
vehicle. You can program this feature using the Driver
Information Center. See
Driver Information Center (DIC)
on page 3-46
As with any vehicle, you should turn on the regular
headlamps if you need them.
3-13

Lamps On Reminder
A reminder chime will sound when your headlamps or
parking lamps are manually turned on and your
ignition is off, in LOCK, ACCESSORY, or your door is
open. To disable the chime, turn the light off, then
back on.
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 lamp control is in AUTO
·the automatic 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 or the last
chosen headlamp setting that was used.
When you turn the exterior lamp control to off, the
headlamps will go off, and your DRL lamps will
illuminate, provided it is not dark outside.
Shifting the transmission into PARK (P) will allow you to
idle the vehicle with the DRL off. The DRL will stay
off until you release the parking brake or shift the
transmission out of PARK (P).
Puddle Lamps
Your vehicle is equipped with puddle lamps to help you
see the area near the base of the front doors when it
is dark out. The puddle lamps will illuminate when a door
is opened or when you press the UNLOCK button on
the keyless entry transmitter.
3-14

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.
To avoid blowing cold air in cold weather, the
system will delay turning on the fan until warm air is
available. The length of delay depends on the
engine coolant temperature. Pressing the fan switch
will override this delay and change the fan to a
selected speed.
9(Off):Press this button to turn off the entire climate
control system. Outside air will still enter the vehicle,
and will be directed to the ¯oor. This direction can
be changed by pressing the mode button. The
temperature can also be adjusted using either
temperature knob. Press the up or down arrows on the
fan switch, the defrost button, the AUTO button, or
the air conditioning button to turn the system on when it
is off.
3-21

Air Bag Readiness Light
There is an air bag readiness light on the instrument
panel cluster, 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 passenger sensing
system (if equipped), the wiring and the crash sensing
and diagnostic module. For more information on the
air bag system, see
Air Bag Systems on page 1-62.
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 air bag readiness light stays on after you start the
vehicle or comes on when you are driving, your air
bag system may not work properly. Have your vehicle
serviced right away.
Air Bag Off Light
When you turn the right front passenger's air bag off,
this light will be lit and stay lit to remind you that the air
bag has been turned off. This light will go off when
you turn the air bag back on again. See
Air Bag
Off Switch on page 1-68for more on this, including
important safety information.The AIR BAG OFF light will
look like one of the following illustrations.
United States with Passenger Sensing System
3-30