Test X: Water-In-Fuel Indicator Inoperative: Description

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2001 GMC Savana Special, 2001 GMC Savana Camper Special, 2001 GMC Savana, 2001 Chevrolet RV Cutaway, and 2001 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.

The fuel manager/filter assembly consists of fuel heater, water-in-fuel sensor, and a filter. Filter contains coalesce, device that combines small droplets of water into larger ones and filter/separator. A fuel lift pump delivers diesel fuel from fuel tank to fuel filter. As fuel enters the filter, fuel passes first though the fuel heater. The heater contains a thermostatic switch, which opens or closes to turn heater OFF or ON, depending on temperature of the fuel. Fuel then passes through the filter and the water coalescer, where droplets of water in the fuel combine into larger drops, that fall into the water reservoir in the filter. When fuel flows from the fuel manager/filter assembly to the injection pump, fuel is clean and free of water. Solid state water-in-fuel sensor supplies voltage to a probe. When the probe touches water, the module closes a switch. This completes a circuit to ground and lights the water-in-fuel indicator. A circuit in water-in-fuel module grounds the light briefly to test the bulb each time ignition switch is turned to RUN position.