Brake Fluid Level Sensor

Worn pads lower the level. It uses a float. It lights the brake warning. A slowly falling level is normal as pads wear, but a sudden drop suggests a leak. Some cars combine the warning with the parking brake warning. Topping up without finding the cause can hide a dangerous leak. The fluid should also be replaced at the intervals given by the manufacturer.

A float switch closes at low level.

Check for leaks immediately. Do not just top up.