3500 4x2 Pickup L6-359 5.9L DSL Turbo (1994)
Water-In-Fuel Sensor: Description and Operation
Water-In-Fuel Sensor
LOCATION
The Water-In-Fuel (WIF) sensor is located at the bottom of the fuel filter/water separator.
OPERATION
The sensor sends an input to the Powertrain Control Module (PCM) when it senses water in the fuel filter/water separator. As the water level in
the filter/separator increases, the resistance across the WIF sensor decreases. This decrease in resistance is sent as a signal to the PCM and
compared to a high water standard value.
Warning Lamp Location
Once the value reaches 30 to 40 kilohms, the PCM will activate the instrument panel mounted, water-in-fuel warning lamp. This all takes place
when the ignition key is initially put in the ON position. The PCM continues to monitor the input at the end of the intake manifold air heater
post-heat cycle.
