Brake Fluid Level Switch On-Vehicle Inspection
WARNING: This page is about a different car, the 2004 Suzuki Vitara. However, it is still accessible from the selected car via links, so may be relevant.
Use an ohmmeter to check switch for continuity. If found defective, replace switch (reservoir).
Brake fluid level switch specification
OFF position (float up): No continuity
ON position (float down): Continuity
Courtesy of SUZUKI OF AMERICA CORP.