On domestic vehicles, when the park brake is applied, the park brake indicator switch closes and supplies ground to the park brake input signal circuit at the daytime running lamps control module (DRL). The DRL then supplies a signal to the park brake input signal circuit at the instrument panel (IPC). The IPC then illuminates the BRAKE indicator. On export vehicles, the park brake indicator switch closes and supplies ground directly to the park brake input signal circuit of the IPC.

When the brake fluid level is low, the brake fluid level indicator sensor closes and supplies ground to the brake fluid input signal circuit at the IPC. The IPC then illuminates the BRAKE indicator, and sends a message to the body control module (BCM) to activate an audible warning.