Brake Warning Indicator: Testing and Inspection

BRAKE LAMP WARNING CIRCUIT DIAGNOSIS





Test Description
The number(s) below refer to step(s) on the diagnostic table.
1. There are three possible symptoms of a problem: the BRAKE warning lamp is always on; the BRAKE warning lamp is never on; the BRAKE warning lamp will not operate for a particular function. This test takes you to the appropriate starting point in the procedure.
2. This test checks whether the Antilock Brake System (ABS) system has turned on the BRAKE warning lamp. If the vehicle is not equipped with ABS, the answer will be No.
4. This steps tests for simple conditions that can turn on the BRAKE warning lamp.
5. This step tests for simple conditions that can turn on the BRAKE warning lamp.
7. This checks whether the master cylinder fluid level switch is faulty.
9. This checks whether the parking brake switch is faulty.
12. This removes the circuit to the Electronic Brake Control Module (EBCM) in a vehicle with ABS.
14. This removes the parking brake switch circuit.
16. This removes the master cylinder fluid level switch circuit.
18. This checks the only remaining circuitry that can activate the BRAKE warning lamp.
20. This tests for the presence of battery voltage used by both the oil pressure lamp and the brake warning lamp.
21. This step begins a sequence that will restore voltage to the lamps.
29. This checks for a burned out indicator lamp.
31. This begins a sequence that will find the open that prevents contact to ground needed to operate the lamp.
33. This checks whether the ABS system has tried to turn on the BRAKE warning lamp and could not. If the vehicle is not equipped with ABS, the answer is No.
34. This step begins a search for a problem in the parking brake switch circuit.
38. This step begins a search for a problem in the master cylinder fluid level switch circuit.














Brake Lamp Warning Circuit Diagnosis