Brake Warning Indicator: Description and Operation

ABS WARNING INDICATOR AND RED BRAKE WARNING INDICATOR (EBC 2 AND EBC 325)
The system is equipped with an amber ABS and a red brake warning indicator to alert the driver of a malfunction it has detected. The CAB can control the operation of both the yellow ABS warning indicator and the red brake warning indicator via CCD BUS.

The CAB controls the ABS warning indicator by making it do one of three things:
^ light steady for 3.4 seconds during an initial test at the beginning of an ignition cycle to function as a bulb check.
^ light steady when a system malfunction exists.
^ light flashing if a vehicle speed signal parameter is faulty or missing.

The Instrument Cluster controls the amber antilock Brake system-warning indicator. All Dodge Truck Instrument Clusters have direct control over the ABS warning indicator and Brake warning indicator. The cluster will periodically transmit a message over the COD bus relating to diagnostics and current indicator status for the ABS and red brake indicator. The cluster will expect a periodic message back from the CAB indicating whether the indicators should be turned on or off. In the event that no signal is received from the CAB for a certain number of times' the cluster will turn on the ABS warning indicator. The indicator provides notice of system-related problems and the need to take diagnostic action.

The vehicle instrument cluster has a red BRAKE warning indicator to alert the driver to the following conditions:
^ parking brake applied
^ hydraulic failure in either front or rear channel
^ ABS system malfunction

The red brake warning indicator is controlled by the vehicle's instrument cluster. There is a parallel path to chassis ground that will illuminate the red brake warning indicator:
^ through the parking brake switch contacts
^ through the combination valve brake warning indicator switch
^ through the CAB via CCD Bus

The CAB can control the operation of both the yellow ABS warning indicator and the red brake warning indicator
^ If the CAB is disconnected, the yellow indicator will be illuminated.
^ If the axle type or tire size are not programmed properly, the yellow indicator will blink.
^ If a system DTC is set, both the yellow and red indicators will be illuminated.
^ If any foundation brake system problem exists.