Interior Lamps
The interior lamps consists of two groups, lamps that can not be dimmed and
lamps that can be dimmed. This first group consists of lamps that may not be dimmed.
This Includes those lamps that may be manually turned on by placing the interior lamp
switch to the DOME position, or by opening a door or a compartment:
• | Auxiliary dome lamp (SEO, RPO 6C7) |
• | Inside rear view mirror lamps |
• | Instrument panel (I/P) compartment lamp |
• | Rear compartment courtesy lamp |
• | Sunshade vanity mirror lamps |
Battery positive voltage is applied at all times to the DIC/RKE fuse and to
the switched side of the BATT RUNDOWN PROTECTION relay in the right I/P junction block.
The DIC/RKE fuse supplies battery positive voltage to the coil side of the BATT RUNDOWN
PROTECTION relay. When the ignition is turned to the ON position, the body control
module (BCM) provides a ground to the courtesy lamp relay control circuit. This energizes
the BATT RUNDOWN PROTECTION relay and applies battery positive voltage to I/P BRP
fuse and to the TRK/ROOF/BRP fuse. Battery positive voltage is applied from the I/P
BRP fuse to the I/P courtesy lamps, I/P compartment lamp and to the courtesy lamp
supply voltage circuit to the BCM. Battery positive voltage is also applied from the
TRK/ROOF/BRP fuse to the:
• | Rear compartment courtesy lamp |
• | Inside rear view mirror lamps |
• | Roof rail/reading lamps assembly |
• | Sunshade vanity mirror lamps |
If the BCM receives a door lock or unlock input signal, the BCM will activate
the BATT RUNDOWN PROTECTION relay, which provides battery positive voltage to all
interior courtesy lamps. When any door is opened, the door jam switch contacts close
and the BCM receives a door-open input signal. The BCM then applies a ground to the
interior lamp control circuit and to the courtesy lamp low control circuit illuminating
the courtesy and dome lamps.
After all the doors are closed, the courtesy lamps remain illuminated for approximately
40 seconds. The courtesy lamps will also turn on and remain illuminated for
approximately 15 seconds after the ignition key is removed, prior to any door
being opened.
When the headlamp switch is placed in the DOME position, the BCM receives a
ground signal. The BCM then applies a ground to the interior lamps control circuit.
This illuminates the dome and roof rail lamps.
The courtesy lamps will normally turn off using the theater dimming feature.
The BCM provides a pulse width modulated ground to all courtesy/reading, dome, and
inside rear view mirror lamps for the theater dimming feature. The BCM will immediately
turn off the courtesy lamps if a door lock command is received with all the doors
closed, or if the ignition switch is turned to either the ON or RUN position.
The BCM activates the interior lighting output 15 seconds after receiving
the class 2 message "Airbags Deployed" from the sensing and diagnostic module
(SDM). The interior lamps remain activated for 25 minutes.
Auxiliary Dome Lamp (SEO, RPO 6C7)
An auxiliary dome lamp on special equipment option (SEO) vehicles is mounted
to the headliner near the windshield. The auxiliary dome lamp is turned ON using a
switch at its base.
Interior Lamps (SEO)
When the emergency vehicle interior lamp switch is turn to the OFF position,
the interior lamps are deactivated immediately.
I/P Compartment Lamp
The I/P BRP provides battery positive voltage to the instrument panel compartment
lamp. When the I/P compartment is opened, a switch closes, providing a ground circuit
to G201, and the I/P compartment lamp illuminates.
Keyless Entry Interior Illumination
When the door key is used to unlock the doors, the BCM receives a door unlock
signal. The BCM activates the interior lamps, provided the BCM has input signals indicating
the following conditions:
• | The ignition switch is OFF |
• | The courtesy lamp switch is OFF |
• | All the doors are closed |
If the door locks are activated to the LOCK position, or if the ignition switch
is turned to either the RUN or CRANK position the courtesy lamps turn off immediately,
otherwise the courtesy lamps will remain on for approximately 40 seconds after
the door is closed. The BCM turns the courtesy lights off through the theater dimming
feature.
If the remote function actuator transmitter is used to unlock the doors or the
trunk, or if the panic button is pressed, the BCM will keep the courtesy lamps on
for approximately 15 seconds. If the door locks are activated to the UNLOCK
or LOCK position, or if the ignition switch is turned to either the RUN or CRANK
position, the courtesy lamps will turn off immediately.
The BCM keeps the courtesy lamps on for approximately 40 seconds after
an alarm event is completed.
The courtesy lamps in special equipment option (SEO) vehicles may be disabled
by using the emergency vehicle interior lamp switch, called surveillance mode.
Rear Compartment Lamp
The TRK/ROOF fuse provides battery positive voltage to the rear compartment
lamp. When the rear compartment is opened, the rear compartment lid ajar switch closes,
providing a ground circuit to G302 and the rear compartment lamp illuminates.
Sunshade Vanity Lamps
The TRK/ROOF fuse provides battery positive voltage to each vanity mirror lamp.
When the vanity mirror cover on the sunshade is opened, a switch closes, providing
a ground circuit to G302, and the vanity lamps illuminates.
Surveillance Mode Switch (SEO)
The surveillance mode switch turns off the daytime running lamps, or low beam
headlamps and tail lamps during low light conditions, instrument cluster, Park, Reverse,
Neutral, Drive, Low (PRNDL) and radio indicators. Interior courtesy lights are also
disabled when the switch is activated.
Interior Lamps Dimming
The second group of interior lighting includes lamps which may be dimmed. This
group uses a combination of class 2 controlled illumination and incandescent
lamps:
• | Door switches and window switches |
• | HVAC control head assembly |
• | Outside rear view mirror switches |
• | Steering wheel controls |
• | Instrument panel cluster (IPC) |
• | Traction control switch |
• | The rear view mirror lamps |
• | Surveillance mode switch (SEO, 9C1/9C3) |
The RH instrument panel (I/P) fuse block supplies battery positive voltage to
both the coil and normally open switch contacts of the park lamp relay. When the body
control module (BCM) energizes the park lamp relay, current flows from
the park lamp relay switched contacts through the REAR PARK LP fuse to the I/P dimming
switch. When dimming is selected, by moving the I/P dimming switch, all incandescent
back lighting lamps (see schematics) and the BCM are provided with a variable voltage
through the instrument panel lamp supply voltage #1 circuit. The incandescent back
lighting lamps are then grounded at G201, G203 and G302. The BCM then applies a message
signal to the class 2 circuit to the IPC and radio. The class 2 displays
then dim to the level set by the I/P dimmer switch. When the I/P dimmer switch is
moved from MIN to MAX, all class 2 displays and all incandescent back lighting
respond from minimum intensity to maximum brightness.
Parade mode may be selected by manually turning on the park lamps during daylight
conditions. The front park lamp circuit supplies voltage the HVAC assembly for a park
lamp on input, and the display will become full bright. The BCM applies a message
signal to the class 2 circuit to the IPC and radio commanding the displays
to become full bright. The surveillance mode switch (SEO) overrides this feature.
Battery Rundown Protection / Inadvertent Power
The body control module (BCM) controls the lighting system through circuits
that enable the park lamps, head lamps and fog lamps as well as the interior lamps.
The BCM opens these enabling circuits 20 minutes after the ignition switch
is turned OFF with no subsequent lamp switch activity. If the ignition switch is
turned to any position other than OFF, or if a lamp switch is activated, during this
20-minute period, the timer will reset for another 20 minutes.