Water In Fuel Light inop
 

My WIF light does not come on when the key is on but my manual says it is supposed to. The diagram in my EVTM says the light is grounded all the time and mine is and the 12v is controlled by the sender. What I don't know is what the wiring is supposed to look like at the sender on the fuel filter because mine is damaged. I have one black wire hanging loose but it is not hot and when I connect it to the sender, the light still doesn't work. Can anyone enlighten me as to how this is supposed to be wired? This is on a 1988 F250 with the 7.3L IDI motor - it's the donor for my diesel Bronco project but I want to make sure all the wiring is working before I do the transplant. Thanks for any help.

unless you get bad fuel, i would not worry about it.
the one in my 88 has never come on, and the wire has been disconnected for at least 15 years now.

Mine has been unplugged for 9 months and I have yet to have an issue. However, the light does come on when I turn the key. It stayed lit last weekend when the truck was running but I think that was because my fuel filter was getting old and that sensor went off. I think the WIF and filter restriction sensors trigger the same light. At least on my 91. I replaced the filter and haven't had the WIF light stay on since.

That being said, you may want to track the WIF cable and the filter restriction cable to the same destination.

That is not true on my '88. If I ground the wire that goes to the filter sensor, a yellow light that says "FUEL FILTER" comes on. It's on the IP to the lower right of the tach.

So, is there just the one black wire that connects to the WIF sensor on the bottom of the filter? My EVTM does not show it that way.

I pulled a 91 motor and installed in an 84 that I had, it did not have a sensor on the ip.

My water separator is laying in the back of my truck... :D

Mine is too haha...

I have never seen an IDI with a sensor like that on the IP. All I have is the FSS, and timing advance. There is nothing near the tach sensor, either. Take some pics because I am confused.

My filter head has a sensor on it that I assume is for filter restriction. I haven't fooled with it, though so maybe that is what you are referring to?

The closest thing that could be confused with a sensor is the switch for the cold start advance and the fast idle solenoid, it is down to the right of the ip.

The sensor is on the top of the fuel filter housing and the other end is the wire on the bottom of the filter. And like everyone has sort of said it really doesn't matter as long as your filter will block water. If it does what will happen is the same thing with dirt. The filter will clog and not let fuel pass and you will not go anywhere. If it bothers you spend $10 by another filter and put it behind your seat just in case. Mines not connected either. I don't have a filter behind the seat and I have never walked to the parts store. I suspect its like a spare tire and most people only need it a couple of times in there life.

the water in fuel sensor is on the bottom of the filter water separator housing on a 7.3
the "sensor" on the top of the filter housing is the fuel heater.
which is also disconnected on my truck for the past 15 or so years.

There are 3 connectors on the fuel filter/heater assy. There are 2 on top, one is the fuel heater and one is the fuel filter sensor. Then there is one on the bottom, that is the WIF sensor. I am trying to find out how it is to be wired up but so far all I get is advise telling me to ignore it.

It should have a black 1 wire 90 * plug for it, then it goes to a little black box laying near the t-stat hsg. about 1 inch square that turns on the Water in fuel light when it senses it. and they do work, mine did a lot and they do not come on with the key

OK, now this is what I am looking for. Mine does have the black wire but the 90* connector is gone and the wire is just hanging loose. I see the little black box you are talking about, mine must be original because it has a Navistar logo on it. But when I ground the black wire with the key on, my WIF light does not come on. Should it?

It should, your little box may be corroded. or the bulb is burned out.