Durango 2WD V8-5.7L (2008)
Cruise Control Indicator Lamp: Description and Operation
Operation
OPERATION
The cruise indicator gives an indication to the vehicle operator when the speed control system is ON, regardless of whether the speed control is engaged.
This indicator is controlled by a transistor on the instrument cluster circuit board based upon cluster programming and electronic messages received by
the cluster from the Powertrain Control Module (PCM) over the Controller Area Network (CAN) data bus.
The cruise indicator Light Emitting Diode (LED) is completely controlled by the instrument cluster logic circuit, and that logic will only allow this
indicator to operate when the instrument cluster receives a battery current input on the fused ignition switch output (run-start) circuit. Therefore, the LED
will always be OFF when the ignition switch is in any position except ON or START. The LED only illuminates when it is provided a path to ground by
the instrument cluster transistor. The instrument cluster will turn ON the cruise indicator for the following reasons:
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Cruise Indicator Lamp-On Message - Each time the cluster receives an electronic cruise indicator lamp-ON message from the PCM
indicating the speed control system is ON, the cruise indicator is illuminated. The indicator remains illuminated until the cluster receives a
lamp-OFF message from the PCM or until the ignition switch is turned to the OFF position, whichever occurs first.
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Actuator Test - Each time the cluster is put through the actuator test, the cruise 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 PCM continually monitors the speed control switches to determine the proper outputs to the speed control servo. The PCM then sends the proper
lamp-ON or lamp-OFF message to the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN). For further
diagnosis of the cruise indicator or the instrument cluster circuitry that controls the LED, Refer to appropriate testing.
For proper diagnosis of the speed control system, the PCM, the EMIC, the CAN data bus or the electronic communication related to cruise indicator
operation a diagnostic scan tool is required. Refer to the appropriate diagnostic information.
