For 1990-2009 cars

### Circuit Operation

The brake warning indicator on the instrument cluster illuminates under the following conditions:

• | The park brake is set

• | The master cylinder brake fluid level is low

• | The electronic brake control module sends a Class 2 message to the instrument cluster

These conditions are explained in detail below.

### Park Brake

The park brake switch closes when the park brake is set. On Domestic and Gulf States vehicles, ground is applied through circuit 1134, the DRL module and circuit 33 to the instrument cluster. The brake indicator illuminates. On Europe and Japan vehicles, ground is applied through circuit 33 to the cluster.

### Brake Fluid Level

When the brake fluid level in the master cylinder is low, the brake fluid level indicator sensor closes. Ground is applied through the sensor and circuit 33 to the instrument cluster. The brake indicator illuminates.

### EBCM Class 2

The brake indicator is also controlled by the ABS system through the Class 2 serial data line. The electronic brake control module (EBCM) sends a Class 2 message to illuminate the brake indicator. The indicator warns the customer that problem exists in the ABS system. Refer to ABS brakes for further information.