Brake Fluid Level Sensor/Switch: Description and Operation

Brake Master Cylinder:

The brake master cylinder fluid level warning switch is an integral part of the brake master cylinder reservoir. It consists of a float containing a magnet and a reed switch mounted in the bottom of the brake master cylinder reservoir.

When the brake fluid in the brake master cylinder reservoir gets to a predetermined level, the floating magnet actuates the reed switch, causing the red brake warning indicator to illuminate; Loss of brake fluid from either the primary (front) hydraulic circuit or secondary (rear) hydraulic circuit will cause the warning indicator to activate.

NOTE: If the brake fluid level warning switch is inoperative, the brake master cylinder reservoir must be replaced.

Refer to Brake Fluid Reservoir service and repair for procedure.