For 1990-2009 cars

Fuse #15 applies voltage to the instrument cluster whenever the ignition switch is in the ON or START position. The brake fluid minimum capacity sensor and the park brake indicator switch control the illumination of the brake indicator lamp.

The park brake indicator switch closes when the parking brake is set. When the park brake indicator switch closes, circuit XM2 is grounded to G103 and the brake indicator lamp illuminates.

The brake fluid minimum capacity sensor closes when the brake fluid level in the master cylinder reservoir is low. When this happens, circuit XA2 is grounded to G103 and the brake indicator lamp illuminates.