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<TD align=middle width="50%">Document ID# 845475
2003 HUMMER
H2 </TD>
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<H1>Interior Lighting Systems Description and Operation</H1><A
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<H5>Interior Lamps</A></H5>
The interior lighting consist of the following two groups. This first group
includes lamps that may not be dimmed.</P>
<UL type=BULLET>
<LI>Courtesy/Illuminated entry lamps
<LI>Dome lamps
<LI>I/P compartment lamp
<LI>Map lamps
<LI>Reading lamps
<LI>Vanity mirror lamps </LI>[/list]<A name=ss2-845475><A
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<H5>Courtesy/Illuminated Entry Lamps</A></H5>
The courtesy/illuminated entry lamps, may be manually turned on or off by
placing the interior lamp switch in the ON or OFF position. If a door is opened,
the courtesy/illuminated entry lamps illuminate. After all the doors have been
closed the courtesy/illuminated entry lamps will remain illuminated
approximately 15seconds. The courtesy/illuminated entry lamps will also
turn on prior to any door being opened, and remain illuminated approximately
40seconds when the driver removes the ignition key. If the interior lamp
switch is turned on when the ignition key is OFF, or the interior lamp switch is
left on when the ignition key is turned OFF the BCM will turn off the courtesy
lamps after approximately 10minutes.</P>
When the driver places the dome lamp defeat switch in the OFF position, the
courtesy/illuminated entry lamps will be disabled, however will still operate
from the interior lamp switch.</P>
The left and right front door courtesy lamps are controlled, and receive
voltage and ground from the drivers door module (DDM) and the passenger door
module (PDM) respectively. The BCM, DDM, and the PDM communicate through class
II serial data for the lamp illumination commands and the door ajar switches.
</P>
The remaining courtesy lamps are controlled and receive voltage from the BCM.
Ground is provided to the footwell lamps and all courtesy/reading lamps at G203.
Ground is provided to the right middle and right rear door at G306. Ground is
provided to the left middle and left rear door at G302.</P><A name=ss3-845475><A
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<H5>Keyless Entry Interior Illumination</A></H5>
When the driver uses the door key in order to unlock the doors, the body
control module (BCM) receives a door unlock signal. The BCM must have inputs
that indicate that the ignition switch is OFF, the courtesy lamp switch is OFF
and all the doors are closed. The BCM will then activate the interior lamps. The
courtesy lamps will remain on, approximately 15seconds after the door is
closed. The BCM will then turn them off through the theater dimming feature. 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 will turn off
immediately.</P>
When the driver uses the remote function actuator transmitter to unlock the
doors, trunk or presses the panic button, the BCM will keep the courtesy lamps
on approximately 40seconds. When the driver uses the remote function
actuator transmitter to lock the doors, the BCM will keep the courtesy lamps on
approximately 2seconds. If the ignition switch is turned to either the RUN
or CRANK position the courtesy lamps will turn off immediately. The BCM will
also keep the courtesy lamps on approximately 40seconds, after an alarm
event is completed.</P><A name=ss4-845475><A
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<H5>Vanity Lamps</A></H5>
The inadvertent power supply voltage circuit of the BCM provides battery
positive voltage to each vanity mirror lamp. When the vanity mirror cover on the
sunshade is opened, a switch closes to provide a ground circuit and the vanity
lamp illuminates. Ground is provided to the vanity lamps at G203.</P><A
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<H5>I/P Compartment Lamp</A></H5>
The inadvertent power supply voltage circuit of the BCM provides battery
positive voltage to the instrument panel compartment lamp. When the IP
compartment is opened, a switch closes to provide a ground circuit and the IP
compartment lamp illuminates. Ground is provided to the IP compartment lamp at
G203.</P><A name=ss6-845475><A
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<H5>Reading Lamps</A></H5>
The inadvertent power supply voltage circuit of the BCM provides battery
positive voltage to the reading lamps. The reading lamps and switch are integral
to the courtesy/reading lamp assembly. When the switch is closed, voltage is
supplied and the lamp illuminates. Ground is provided to the reading lamps at
G203.</P><A name=ss7-845475><A
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<H5>Battery Rundown Protection/Inadvertent Power</A></H5>
The BCM inadvertent power supply voltage circuit provides battery positive
voltage to all of the interior reading lamps, I/P compartment lamp, and both
visor vanity mirror lamps. In the event that any of these lamps were to remain
illuminated for a period of more than 10minutes with the ignition switch
in the OFF position, the BCM will deactivate the inadvertent power supply
voltage circuit to prevent a total battery discharge condition. </P>
The BCM also utilizes the inadvertent power supply voltage circuit as a lamp
request signal circuit when none of the lamps in the circuit are illuminated.
When a lamp switch is activated, the BCM receives the request for lamp
illumination and switches to supplying voltage to the inadvertent power supply
voltage circuit.</P><A name=ss8-845475><A
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<H5>Interior Lamps Dimming</A></H5>
The second group includes lamps which may be dimmed. This group may use a
combination of vacuum fluorescent (VF) illumination and incandescent lamps.</P>
When the ignition switch is turned to the RUN position, the radio's vacuum
fluorescent (VF) displays turn on at maximum brightness. When the park lamps are
on, all incandescent back lighting turn on at the dimming level indicated by the
I/P dimmer switch. At the same time all vacuum fluorescent (VF) displays dim to
match the indicated dimming level. The panel dimmer switch potentiometer is an
input to the BCM. When the driver selects a dimming setting by moving the I/P
dimming switch potentiometer, all incandescent back lighting lamps are provided
with a specific voltage. When the I/P dimmer switch is moved from MIN to MAX,
all vacuum fluorescent (VF) displays, as well as all incandescent back lighting
respond from minimum intensity to maximum brightness in response to the I/P
dimmer switch. </P>
<UL type=BULLET>
<LI>The instrument panel cluster (IPC)
<LI>Radio
<LI>Window and heated seat switches
<LI>Garage door opener switch
<LI>Sunroof switch
<LI>HVAC control assembly
<LI>Headlamp and panel dimmer switch
<LI>Tow/haul switch
<LI>Transfer case shift control switch
<LI>Height control switch
<LI>PSIR disable switch
<LI>PRNDL lamps
<LI>Traction control switch
<LI>Steering wheel control switches
<LI>Rear wiper/washer switch </LI>[/list]
The left and right front door switch illumination is controlled, receivies
voltage and ground from the drivers door module (DDM) and the passenger door
module (PDM) respectively. The radio is also a class II module and has full
control of its illumination. The BCM, DDM, PDM, and radio communicate through
class II serial data for the lamp illumination commands</P>
The I/P cluster illumination lamps receive voltage and are controlled by the
BCM on the instrument panel lamps dimming supply voltage circuit. Ground for the
instrument panel lamps is at G203.</P>
The various switches, HVAC control assembly, and the PRNDL lamps receive
voltage and are controlled by the BCM on the instrument panel lamps dimming
control circuit. Ground for the rear window switches is at G302 and G306. Ground
for the traction control switch, steering wheel controls, and the rear
window/wiper switch is at G200. Ground for the remaining switches is at
G203.</P>
<UL type=BULLET>
<LI>Traction control switch traction control OFF indicator
<LI>Height control switch high clearance indicator
<LI>Transfer case control switch 4WD position indicator
<LI>Headlamp and panel dimmer switch Headlamp ON indicator
<LI>Headlamp and panel dimmer switch DRL OFF indicator </LI>[/list]
The indicators receive voltage from the BCM on the LED dimming circuit.
Ground/control for the indicators is from the various modules. The modules
controlling the above indicators are as follows:</P>
<UL type=BULLET>
<LI>Electronic brake control module (EBCM)
<LI>Electronic suspension control module
<LI>Transfer case shift control module
<LI>Body control module (BCM) </LI>[/list]
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<TD align=middle width="50%">Document ID# 845475
2003 HUMMER
H2 </TD>
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