Dakota 4WD V8-4.7L VIN J (2007)
Hi-Beam Indicator Lamp: Description and Operation
Operation
OPERATION
The high beam indicator gives an indication to the vehicle operator whenever the headlamp high beams are illuminated. This indicator is controlled by a
transistor on the instrument cluster circuit board based upon cluster programming and a hard wired multiplex input received by the cluster from the
headlamp beam select switch circuitry of the multi-function switch on the washer/beam select switch mux circuit.
The high beam indicator Light Emitting Diode (LED) is completely controlled by the instrument cluster logic circuit, and that logic will allow this
indicator to operate whenever the instrument cluster receives a battery current input on the fused B(+) circuit. Therefore, the LED can be illuminated
regardless of the ignition switch position. The LED only illuminates when it is provided a path to ground by the instrument cluster transistor. The
instrument cluster will turn ON the high beam indicator for the following reasons:
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High Beam Headlamps-On Input - Each time the cluster detects a high beam headlamps-ON input from the headlamp beam select switch
circuitry of the multi-function switch on the washer/beam select switch mux circuit, the headlamp high beams and the high beam indicator will be
illuminated. The indicator remains illuminated until the cluster receives a high beam headlamps-OFF input from the multi-function switch, or until
the exterior lamp load shedding (battery saver) timed interval expires, whichever occurs first.
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Actuator Test - Each time the cluster is put through the actuator test, the high beam indicator will be turned ON, then OFF again during the bulb
check portion of the test to confirm the functionality of the LED and the cluster control circuitry.
The Electromechanical Instrument Cluster (EMIC) continually monitors the headlamp switch and the multi-function switch to determine the proper
headlamp low beam and high beam control. The EMIC then sends the proper electronic low beam and high beam lamp-ON and lamp-OFF messages to
the Front Control Module (FCM) over the Controller Area Network (CAN) data bus and controls the high beam indicator operation accordingly. For
further diagnosis of the high beam indicator or the instrument cluster circuitry that controls the indicator.
The hard wired headlamp switch and multi-function switch inputs and circuits related to high beam indicator operation may be diagnosed using
conventional diagnostic tools and procedures. Refer to the appropriate wiring information. For proper diagnosis of the FCM, the EMIC, the CAN data
bus or the electronic communication related to high beam indicator operation a diagnostic scan tool is required. Refer to the appropriate diagnostic
information.
