The brake 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. On vehicles equipped with anti-lock braking system, the float has an integral mesh screen for filtering.
When the brake fluid in the brake master cylinder reservoir gets to a predetermined level, the float and magnet actuates the reed switch that causes the red brake warning indicator to illuminate. Loss of brake fluid from either the primary (front) or secondary (rear) system will cause this system to activate. If the brake fluid level warning switch is inoperative, the brake master cylinder reservoir must be replaced.
