Circuit Operation
The brake warning indicator on the instrument cluster illuminates under the following conditions:
| • | Ignition in the start position |
| • | The park brake is set |
| • | The master cylinder brake fluid level is low |
| • | The electronic brake control module applies ground to the instrument cluster |
These conditions are explained in detail below.
Park Brake
The park brake switch closes when the park brake is set. Ground is applied to the DRL module circuit 1830 and from the DRL module circuit 233 to the body control module (BCM) which will illuminate the brake indicator through the Class 2 serial data line.
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 209 to the instrument cluster. The brake indicator illuminates.
EBCM/EBTCM
The brake indicator indicator is also controlled by the ABS system through the Class 2 serial data line. The electronic brake control module / electronic traction control module (EBCM/EBTCM) applies ground through the Class 2 serial data line to illuminate the brake indicator. The indicator warns the customer that problem exists in the ABS system. Refer to ABS brakes for further information.
