AutoSig System senses water in the fuel separator with. Designed to pass UL 1105, ABYC and US Coast Guard Fuel System standards. Water-in-fuel WIF Sensor Probe is INSIDE the filter housing; Sensors, Detectors, Transducers; Filters; Separators; Consulting Services; Controls and Controllers; Engineering Services; Harnesses; Kits; Research, Design and Development Services ...