The hermetically sealed reed sensor is the best choice and satisfies all the brake fluid sensing requirements. In this case, a float with an imbedded magnet is placed within the brake fluid tank in an area where it can ride up and down with the brake fluid. The reed switch is directly mounted to a printed circuit board which also houses a high kilo-ohm resistor with two rugged terminals. These components are further housed in a plastic sealed package that locks in place in the lower external section of the brake fluid tank. The reed sensor is plugged into a sealed automotive electrical connector allowing connection to the vehicle electrical system.