Brake Warning Indicator: Description and Operation

CIRCUIT OPERATION
The "BRAKE" Indicator, when lit, alerts the driver that the Parking Brake is engaged or that there is an insufficient amount of Brake Fluid in the Master Cylinder Reservoir. If the vehicle is equipped with the Antilock Brake System (ABS), the Electronic Brake Control Module (EBCM) will turn on the "BRAKE" Indicator along with the "ABS" Indicator to alert the driver that there is a malfunction within the ABS which has affected the vehicle's base braking system. The "BRAKE" Indicator will also light when the Ignition Switch is turned to "START." This is called the Bulb Test Check.

Voltage to the "BRAKE" Indicator is provided through the GAUGE Fuse, Junction Block 1, the Audio Alarm Module and Junction Block 3. If the Parking Brake is engaged, then the Parking Brake Switch is closed. Since the Parking Brake Switch is case grounded, the "BRAKE" Indicator lights when the parking brake is engaged. If the brake fluid level is low enough, then the Brake Fluid Level Switch, located within the Master Cylinder Reservoir, is closed. Since the Brake Fluid Level Switch is grounded at G104, the "BRAKE" Indicator lights whenever there is a low brake fluid condition.

If the vehicle is equipped with ABS and the "BRAKE" Indicator and "ABS" Indicator are lit simultaneously, then a ground has been provided to the "BRAKE" Indicator by the EBCM. This alerts the driver that a problem exists within the ABS which is affecting the action of the base braking system.

The Bulb Test Check operation of the "BRAKE" Indicator occurs only when the Ignition Switch is turned to "START." With the Ignition Switch in "START," voltage flows through the Clutch Pedal Position (CPP) Switch when the Clutch Pedal is fully depressed (manual transaxle) or the Park/ Neutral Position (PNP) Switch when the Manual Selector Lever is in "P" or "N" (automatic transaxle) to the Bulb Check Relay. Since the Bulb Check Relay is grounded at G200, the transistor is turned ON. With the transistor turned ON, a ground is provided to the "BRAKE" Indicator and the bulb lights.