Circuit/System Description
WARNING: This page is about a different car, the 2019 Buick Cascada, 2018 Buick Cascada, and 2017 Buick Cascada. However, it is still accessible from the selected car via links, so may be relevant.
The electronic brake control module monitors the brake fluid level in the brake fluid reservoir. When the fluid within the brake fluid reservoir is below the MIN level, contacts within the brake fluid level switch closes causing the voltage within the signal circuit to drop. The electronic brake control module will detect the voltage drop and will send a serial data message to the instrument cluster commanding the brake warning indicator to illuminate.