Instruments (Water sensor): Description and operation

Water sensor

On vehicles with diesel engines a water sensor is located in the bottom of the fuel filter. The sensor utilises the different resistance properties between water and diesel fuel to determines the presence of water in the fuel.

The sensor receives a battery voltage supply from the fuel pump relay. The sensor output is supplied to the instrument pack. The water sensor provides the earth path to illuminate the warning lamp. l < 1.8 volts = warning lamp on. l > 7.7 volts = warning lamp off.