Brake Warning Lamp on

Brake Warning Lamp ON






Circuit Description
The Electronic Brake Control Module (EBCM) controls the operation of the 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".

The default state is for the Lamp Driver Module to turn ON the Brake Warning Lamp, by supplying a ground path through the Lamp Driver Module.

When the EBCM commands the Brake Warning Lamp off, the EBCM will ground the ABS 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 MANDO MGH25 ABS system, the EBCM may turn ON the Brake Warning Lamp, notifying the driver that either Brake System or MGH25 needs to be serviced.

Diagnostic Aids
Typical causes of the Brake Warning Lamp on with no DTC(s) set.
1) Faulty Emergency brake switches.
2) Low brakes fluid level or faulty brake fluid switch.
3) DDPR is disabled due to the following fault conditions in MGH-25 ABS system.
a)
^ Two Wheel Speed Sensors inoperative on same axle.
^ Battery 2(Motor Input) short to ground.
^ Battery 1(ECU Input) Open or short to ground.
^ Motor ground open or short to battery.
^ ECU ground open or short to battery.
^ Ignition open or short to ground.

4) Grounded circuit between the Cluster and the EBCM.
5) Faulty Cluster/Lamp Driver Module.
6) Faulty EBCM.








Troubleshooting