on 2003 ....the little light will come on for a few minutes then go off stay off then come back on the next day....
was told to look for a yellow drain plug at the filter, not there...

 

When you find it. which will be shortly. get your self one of these:

DTS Articles - HFCM Water Separator Drain Plug Upgrade

By the picture, you can see where on the lower filter (HFCM) the drain is located.I think it is a 6mm hex plug. They tend to strip.

 

Look on your fuel pump/water separator thats mounted in the frame rail in the area of the drivers side door. You will see a plug with a 6mm allen hole in the plug, remove the plug and drain. If the WIF light still keeps coming on and you are satisfied there is no water in what your draining, then the sensor is sludged up giving you false readings.

 

Good resource for information like this is in the tech-folder at the top of the thread page.


https://www.ford-trucks.com/forums/3...ch-folder.html



Here is a good how to from there:


http://www.dieselfiltersonline.com/D...ence-Guide.pdf