Bulb Test - Each time the ignition switch is turned to the ON position the brake indicator is illuminated
by the instrument cluster for about three seconds as a bulb test.
Brake Indicator Lamp-On Message - Each time the cluster receives an electronic brake indicator
lamp-ON message from the CAB, the brake indicator will be illuminated. The CAB may also send lamp-
ON messages as feedback during ABS diagnostic procedures. The indicator remains illuminated until the
cluster receives a lamp-OFF message from the CAB, or until the ignition switch is turned to the OFF
position, whichever occurs first.
Park Brake Switch Input - Each time the cluster detects ground on the park brake switch sense circuit
(park brake switch closed = park brake applied or not fully released) while the ignition switch is in the
ON position, the brake indicator flashes ON and OFF. The indicator continues to flash until the park
brake switch sense input to the cluster is an open circuit (park brake switch open = park brake fully
released), or until the ignition switch is turned to the OFF position, whichever occurs first.
Antilock Brake System (ABS) Indicator Backup - If the instrument cluster detects a fault in the ABS
indicator circuit it will send a message indicating the fault to the Controller Antilock Brake (CAB), then
flash the brake indicator ON and OFF. The cluster will continue to flash the brake indicator until the ABS
indicator circuit fault is resolved, or until the ignition switch is turned to the OFF position, whichever
occurs first.
Actuator Test - Each time the instrument cluster is put through the actuator test, the brake 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 park brake switch on the park brake lever mechanism provides a hard wired ground input to the instrument
cluster circuitry through the park brake switch sense circuit whenever the park brake is applied or not fully
released. The Totally Integrated Power Module (TIPM) monitors the brake fluid level switch on the brake
master cylinder reservoir, then sends the appropriate electronic messages to the CAB. The CAB continually
monitors the ABS system circuits and sensors to decide whether the system is in good operating condition. The
CAB then sends the proper lamp-ON or lamp-OFF message to the Electro Mechanical Instrument Cluster
(EMIC) (also known as the Cab Compartment Node/CCN). If the CAB sends a lamp-ON message after the bulb
test, it indicates that the CAB has detected a brake hydraulic system malfunction or that the ABS system has
become ineffective. The CAB will store a Diagnostic Trouble Code (DTC) for any malfunction it detects.
The hard wired park brake switch input to the EMIC may be diagnosed using conventional diagnostic tools and
procedures. Refer to the appropriate wiring information. For proper diagnosis of the brake fluid level switch, the
ABS, the CAB, the EMIC, the TIPM, the CAN data bus or the electronic communication related to brake
indicator operation a diagnostic scan tool is required. Refer to the appropriate diagnostic information.
DIAGNOSIS AND TESTING
BRAKE INDICATOR
WARNING:
To avoid serious or fatal injury on vehicles equipped with airbags, disable
the Supplemental Restraint System (SRS) before attempting any steering
wheel, steering column, airbag, Occupant Classification System (OCS),
seat belt tensioner, impact sensor, or instrument panel component
diagnosis or service. Disconnect and isolate the battery negative (ground)
cable, then wait two minutes for the system capacitor to discharge before
2007 Dodge Nitro R/T
2007 ACCESSORIES AND EQUIPMENT Instrument Cluster - Service Information - Nitro