1. Disconnect the brake fluid level sensor connector from the master cylinder.
2. Inspect for continuity according to fluid level between the brake fluid level sensor terminals.

If not as indicated in the table, replace the reserve tank.

Brake Switch InspectionClutch Release Collar Inspection [C66 M R]
CAUTION:
Do not clean the clutch release collar with cleaning fluids or a steam cleaner
because it is filled with grease.
Operation Inspection
1. Turn the collar while applying force in the axial direction, and inspect for
sticking, excessive resistance, and an abnormal noise.
...
Warranties for Your Mazda
New Vehicle Limited Warranty
Powertrain Limited Warranty
Safety Restraint System Limited Warranty
Anti-perforation Limited Warranty
Federal Emission Control Warranty/California Emission Control Warranty
Emission Defect Warranty
Emission Performance Warranty
Emission Control ...
Filament Inspection
1. Turn the ignition switch to the ON position.
2. Turn the rear window defroster switch on.
CAUTION:
Directly touching the rear window defroster filament with the lead of the
tester could damage it. Wrap aluminum foil around the end of the lead and inspect
the filament by touc ...