What are the yellow and red circled wires on top of the fuel filter on a 1994 n/a? I am changing my fuel filter because the "water in the fuel" light started blinking then went out. The current filter is WIX 33417 which does not have the water sensor port. Did Ford move the sensor to the filter housing in `94? Some cause the WIF light to come on.

I have one unconnected wire in the area (black with 90 degree butt connector) of the filter but it does not have a probe on the end. What does the probe look like and what is the part number? The truck will be parked for extended periods so a water sensor is needed.

Also, is the fuel inlet (blue circle) 1/2 NPT or is it metric. Best I could measure was .517. I want to put a check valve there to help address air intrusion and need to know the size to get. I found a Doorman 800-195 with 5/16 threads. That will be too small. Does any one know of a check valve that will bolt on. I still have the hard line between the pump and filter.

 

The red circle is your fuel heater connection. The yellow is the sensor for fuel restriction,or what would make your fuel filter light come on. The water in fuel sensor is at the bottom of the filter in either the screw on bowl or if you get the one piece filter with the sensor at the bottom. I dont know about the check valve size.