Chrysler 300M 1999, Manual, Page: 19 / 766

3.6.4 Rear Window Defogger
When the BCM receives a rear defogger request from the climate control head (either ATC or
manual) the BCM will activate the rear window defogger relay for 15 minutes. If the BCM receives
another rear defogger request while the relay is still activated, the relay will be de-activated. If the
relay is allowed to time out (full 15 minutes), further requests during the same ignition on period
will cause the BCM to activate the relay for 7.5 minutes.
3.7 Exterior Lighting System
3.7.1 Exterior Lighting Battery Saver
The BCM monitors the status of and controls the park lamp, head lamp and fog lamp relay’s. If
any exterior lamps are left on after the ignition is turned off, the BCM will turn the headlamps and
fog lamps off after 10 minutes, the park lamps will remain on.
3.7.2 Headlamp Delay
The headlamp time delay operates when the ignition switch is turned off while the headlamps are
still on, and the headlamps are then turned off within 45 seconds after the ignition is off. This will
provide a 90-second time delay before turning off the headlamps.
3.7.3 Headlamp Switch
The headlight switch on 300M vehicles use a multiplexed (MUX) circuit to the BCM. The BCM will
then control the park lamp, head lamp and fog lamp relay’s based on this input.
3.7.4 Fog Lamp Control
The body control module controls the operation of the fog lamp relay which controls the fog lamps.
The fog lamps can only be on if the park or low beam headlamps are on. If the high beams are
turned on, the fog lamps will remain on.
3.8 Interior Lighting
3.8.1 Courtesy Lamp Control
The body controller has direct control over the majority of the vehicle’s courtesy lamps. The body
computer will illuminate the courtesy lamps under any of the following conditions:
1) Any door is ajar.
2) The courtesy lamp switch on the instrument panel is closed.
3) A Remote Keyless entry unlock message is received. If the interior lamps are left on after the
ignition is turned off, the BCM will turn them off after 1 hour or until either the dome lamp switch
or door ajar switch changes state.
3.8.2 Illuminated Entry
Illuminated entry will be initiated when the customer enters the vehicle by unlocking the doors with
the key fob, or with the key if the vehicle is equipped with vehicle theft alarm. Upon exiting the
vehicle, if the lock button is pressed with a door open, illuminated entry will cancel when the door
closes. If the doors are closed and the ignition switch is turned on, the illuminated entry also
cancels.
3.9 Mechanical Instrument Cluster
The instrument cluster displays four gauges, a vacuum fluorescent (VF) odometer, a VF PRNDL
and up to (18) indicators. One reset button is used to switch the display from trip to total. Holding
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