fuel selector Problem

[rodymartin]

Well it has been a rough winter with very rough roads. Now I have a problem with the fuel tank selector It does not switch tanks the fuel gauge reads full or works right some times. I am running on the front tank right now but have a full tanks in the rear.


Does anyone have wiring diagram for the F250 wiring on a 85 with duel tanks I can get online to trouble shot this?

 

[Agnem]

You'll find a usable schematic in my Moosestang album (link in sig). The FSV has 5 wires going to it. #1 and #2 power the motor. There are contacts and diodes in the motor that limit and control direction of travel. Wires 3 through 5 comprise a SPDT switch which routes the fuel gauge to the sender of whatever tank is selected. Removing the plug from the FSV will allow you to ohm out the contacts on the FSV. Connecting 12 volts to pins 1 and 2 one way, and then reversing those connections should allow you to hear the motor run (it only takes a fraction of a second to switch though). What often happens is the brushes loose contact with the commutator, and the motor dies. Or the contacts go bad and it cannot reverse direction. The unit is rivited or glued together. I've never tried it, but an enterprising person may be able to disect one and repair it.

 

[rodymartin]

Is the wiring for the 85 the same as the 90? That one I have.

 

[CJCJ]

I don't know about the schematics being the same but mine ended up being the fuse, it must have worked it's way out 4x'in.

 

[Goofyexponent]

I just had the same damn thing happen....I am looking into seeing if my old 1996 4.9 gas selector will work on the 1993 diesel.....i will let you know for sure what happens when i tear it apart and see what i have to work with.

 

[Goofyexponent]

I found my problem....I was working on my truck a week ago and pulled a fuse out of the A/C to replace a blown taillight fuse. I didn't put a new fuse back in because A/C isn't for real men lol. I was just about to pull the divider off the truck and I thought I better check to see if there was a fuse. Sure enough....it is the same fuse the A/C runs off of. If I remember right it's fuse #6.