Brake Warning Indicator Inoperative

Brake Warning Indicator Inoperative

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 11, and the electronic brake control module terminal 13 when the ignition switch is turned ON. EBCM terminals 1 and 2 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 turn ON the ABS warning lamp for 3 seconds for a bulb check.

Whenever a malfunction is detected within the general brake system or DDRP, the EBCM may turns ON the brake warning lamp, notifying the driver that either brake system or DDRP needs to be serviced.

Diagnostic Aids

Typical causes of the ABS warning lamp inoperative with no DTCs set:

* Faulty bulb/loose socket
* I/P fuse open
* Faulty cluster/lamp driver module
* Faulty EBCM
* Grounded circuit between the EBCM and the cluster

Step 1 - Step 7:

Step 8 - Step 12:

Step 13 - Step 15: