Interior Lighting Systems Description and Operation
Interior Lamps
The interior lamps consist of 2 groups, those which can dim from
the instrument panel cluster lamps dimmer switch and those that can
not dim.
Courtesy/Illuminated Entry Lamps
The following lamps may be manually turned ON by placing the
interior lamp switch in the ON position, or by opening a door while
the switch is in the AUTO position.
The courtesy lamp supply voltage circuit of the body control
module (BCM) supplies battery positive voltage to the dome lamp,
the liftgate lamps and courtesy lamps. When any door is opened, the
door jamb switch contacts close providing a door open input to the
BCM. The BCM then provides a B+ to the interior lamps with the
switch in the AUTO position. The interior lamps receive a ground
when the switch is in the ON position.
Note: If the liftgate is
opened after all the modules go to sleep, the dome light will not
come on. The liftgate ajar switch input to the BCM will not wake up
the BCM once it has gone to sleep, so the dome light will not come
on. Once the BCM gets an input to wake it up, from remote keyless
entry or a door handle, the dome light will turn on when the
liftgate is opened.
If the driver inadvertently leaves any interior lamp ON, the BCM
will turn it OFF after a 20 min time-out.
The courtesy lamps will turn OFF immediately if the ignition
switch is turned to the ON position or approximately 20 s after all
doors are closed.
Keyless Entry Interior Illumination
When the BCM receives a door unlock command from the remote
keyless entry transmitter, the BCM will flash the park lamps
several times, illuminate the courtesy and park lamps, and
illuminate the low beam headlamps at low intensity. The lamps will
remain on until the ignition key is turned from the OFF position, a
keyless entry transmitter door lock command is received, or after
an approximate 20 s delay.
Interior Lamps Dimming
This group includes lamps which may dim. This group may use a
combination of vacuum fluorescent illumination, LEDs and
incandescent lamps.
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HVAC control module, head
assembly |
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Rear HVAC control module, head
assembly |
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The instrument panel
cluster |
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The PRNDL lamp, with the
exception of the current gear select position |
When the ignition switch is turned to the ON position, the
vacuum fluorescent display, radio, turns ON at maximum brightness.
When the park lamps or low beams are ON, all incandescent back
lighting turn ON at the dimming level indicated by the instrument
panel cluster dimmer switch. At the same time all fluorescent
display displays dim to match the indicated dimming level. When the
headlamp switch is placed in the PARK or in HEADLAMPS position, the
headlamp switch supplies an input signal to the BCM. The BCM then
supplies voltage to the instrument panel cluster dimmer switch
through the dimming control circuit. The setting of the instrument
panel cluster dimmer switch determines the amount of voltage that
the instrument panel cluster dimmer switch supplies to the BCM. The
BCM then sends a PWM voltage to all the interior lamps. All the
fluorescent display and incandescent back lighting lamps are
provided a specific voltage.
Note: For vehicles which
are equipped with automatic light function, the interior
backlighting can only be dimmed when the ambient light sensor
detects night conditions.
When the headlight switch is turned to the park lamp or headlamp
position, all incandescent back lighting turn ON at the dimming
level indicated by the instrument panel cluster dimmer switch. When
the instrument panel cluster dimmer switch is moved from minimum to
maximum, all fluorescent display displays, as well as all
incandescent back lighting respond from minimum intensity to
maximum brightness in response to the instrument panel cluster
dimmer switch.
Inadvertent Power
The BCM used in this vehicle controls the lighting system
through circuits that enable the interior lamps. The BCM opens
these enabling circuits shortly after the ignition switch is turned
OFF with no lamp switch activity. If the ignition switch is turned
to any position other than OFF, or if a lamp switch is activated
during this period, the timer will reset itself.
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