Dodge ZB 2005 Service Manual page 1392

3.6 DOOR AJAR SYSTEM
The door ajar and decklid ajar states are used as
inputs for the Body Control Module (BCM). The
BCM uses these inputs to determine exactly what
position the doors and trunk are in. The DRBIII
will display the state of the door ajar and the
decklid ajar switches in Inputs/Outputs. It's impor-
tant to note, that when any door, or the decklid is
closed, the switch state on the DRBIII will show
OPEN. When any door, or the decklid is open the
switch state on the DRBIII will show CLOSED.
During diagnosis, if a door or the decklid is closed
and the DRBIII displays the switch state as
CLOSED, it indicates a shorted ajar circuit. If the
door or the decklid is open and the DRBIII dis-
plays the switch state as OPEN, it indicates an
open ajar circuit.
GENERAL INFORMATION
3.7 EXTERIOR LIGHTING SYSTEM
3.7.1 HEADLAMP POWER
The headlamp switch is a direct input to the
BCM. The BCM then turns on power to the head-
lamp low beams using a relay and power to the high
beams through two "fuseless" circuits. These cir-
cuits are electronically controlled and continuously
monitored for malfunctions. Power is supplied to
each filament in a separate circuit.
3.7.2 HEADLAMP SWITCH
The Headlamp Switch uses four separate circuits
(inputs) to the Body Control Module (BCM) plus one
circuit as a sense ground return. The Headlamp
Switch controls the Fog lamps, Park lamps and the
Low beam relay and High beam headlamps.
3.7.3 PARK LAMP
The park lamp switch is a direct input to the
BCM. The park lamp is then powered through a
high side driver in the BCM. This circuit is electron-
ically controlled and continuously monitored for
malfunctions.
3.7.4 FOG LAMP/DRL's
The fog lamp switch is a direct input to the BCM.
The left and right fog lamps are powered through
two high side controls in the BCM. This circuit is
electronically controlled and continuously moni-
tored for malfunctions.
3.7.5 FOG LAMPS
The BCM controls the operation of the fog lamps.
Fog lamps can only be ON when the park and low
beams are ON. If the high beams are switched ON
then the Fog lamps will be automatically turned
OFF.
3.7.6 EXTERIOR LIGHTING BATTERY
SAVER
The BCM monitors the status of, and controls, the
Park Lamps, Headlamps and Fog Lamps. If any
exterior lamps are left ON after the ignition is
turned OFF, the BCM will turn them OFF after 3
minutes.
3.8 RELAYS CONTROLLED BY THE BCM
Low beam relay
The lowbeam switch is a direct input to the BCM.
The lowbeam lamp relay is then powered through
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