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CIRCUIT DESCRIPTION
The Electronic Brake Control Module (EBCM) controls the ANTILOCK indicator lamp illumination by supplying a ground to terminal B. When the vehicle is started or the ignition is turned to the RUN position, the ANTILOCK indicator should illuminate for three seconds and turn off. A ground will also be supplied to the ABS indicator lamp through contacts A9 and B8 of the electronic brake control lamp relay if the 10-way EBCM connector is unseated or disconnected.

DIAGNOSTIC AIDS
If the ANTILOCK indicator lamp is on always with no Diagnostic Trouble Code (DTCs) set (never turns off after three seconds with the vehicle started or with the ignition switch in the RUN position), check for the proper connection of the 10-way Electronic Brake Control Module (EBCM) harness connector. Check for a failed electronic brake control lamp relay. If no problems are found, then there could be a short to ground in CKT 867 between the instrument cluster and the EBCM, or an open in the power or ground circuits to the electronic brake control lamp relay, or the EBCM is internally shorted to ground on C1 terminal B, or open internally on C1 terminal K.

TEST DESCRIPTION
The numbers below refer to the steps in the diagnostic table:
3. This step removes the ABS safeguard indicator circuitry from consideration as the cause of the fault.
4. This step checks the ground circuit from the Electronic Brake Control Module (EBCM) to the electronic brake control lamp relay.
5. This step decides between a faulty ground in the EBCM terminal K or CKT 451.
6. This step decides between a faulty electronic brake control lamp relay, or an open in CKT 441.