Fluid Level Sensor
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2008 Suzuki Reno, 2008 Suzuki Forenza, 2007 Suzuki Reno, 2007 Suzuki Forenza, and 2006 Suzuki Reno. However, it is still accessible from the selected car via links, so may be relevant.
The master cylinder is equipped with a fluid level sensor. This sensor will activate the BRAKE light if a low fluid level condition is detected. Once the fluid level is corrected, the BRAKE light will go out.