When the water level in the water separator reaches the warning level, the WiF sends an electrical signal to the ECU or to dashboard (lamp).
[1] The WiF is often used in common rail engines to avoid fuel injector damage.
[3] First generation WiF sensors use a potting resin to isolate the electronic circuit, while the latest generation of WiF sensors (the WS3 sensor in surface-mount technology) are made totally without leakage using an innovative co-molding process.
The latest generation of WiF sensors have a high resistance to vibrations and to thermal excursion cycles.
The main automotive WiF designer and producer is SMP Poland.