Brake Warning Lamp Inoperative / No DTC Set

Brake Warning Lamp Inoperative / No DTC Set






Circuit Description
The Electronic Brake Control Module (EBCM) controls the operation of the red Brake Warning Lamp by means of a lamp driver module contained within the Cluster.

Battery voltage is supplied to the I/P Cluster terminal B14, and EBCM terminal 4 when the ignition switch is turned on EBCM terminals 9 and 25 are hot at all times.

When the EBCM commands the Brake Warning lamp off, the EBCM will ground the Brake Warning Lamp control circuit. This causes the Lamp Driver Module to open the path to ground for the bulb. When the ignition switch is turned to the ON position, the EBCM turns ON the Brake Warning Lamp for 3 seconds for a bulb check.

Whenever a malfunction is detected within the General Brake system or DDRP, the EBCM turns ON the Brake Warning Lamp, notifying the driver that Brake System or DDRP needs to be serviced.

Diagnostic Aids
Typical causes of the Brake Warning Lamp inoperative with no DTC(s) set.
1) Faulty bulb/ loose socket.
2) I/P fuse open.
3) Faulty Cluster/Lamp Driver Module.
4) Faulty EBCM.
5) Grounded circuit between the EBCM and the Cluster.








Troubleshooting