Duel tank switch?

[96Rivman]

Ok fellow Ford owners I need some help. My sons 96 F150 with dual tanks will only work on the rear tank. As soon as it's switched to the front the truck dies. I ohmed out the switch on the dash and it seems to be working properly. My question is this, where is the switch/valve located under the truck that switches the two tanks? Thanks

[Johnny Mullet]

I would first check to see if the fuel pump in that tank is working.

[bearcat329]

i have a 1994 f-350 crewcab dually with the exact same problem, please keep us posted on what you find, and i'll do the same
Rick, Ore

[Torch]

Follow the fuel lines from the tanks and start heading for the front of the truck, eventually you will find the switcher valve, the switcher-valve on my '77 F250 was directly under the driver bolted to the bottom side of the truck.

[96Rivman]

After looking at ALLDATA I don't think the truck has a switch other than the one on the dash board. I am leaning towards the front tank fuel pump. I am going to ohm out the switch on the dash and see if the front pump is getting power when I switch it and if it is it has to be the pump. I'll keep you posted.

[96Rivman]

Ohmed out the red wire off the switch on the dash and I am getting voltage so it appears that I need to install a new fuel pump in the front tank.

[Johnny Mullet]

There are pumps in each tank (low pressure) and another (high pressure) pump in that system if I remember correctly.

[unclebubbles]

I believe that Ford used the system that Johnny Mullet is talking about from 87-89 . Starting in 90 i think, they no longer used the externally mounted high pressure pump and had a high pressure pump in each tank. The switching valve is actuated by pump pressure. Take the harness connector loose for the front tank, and hook a test light or voltmeter to the red and the black wire in the connector. (vehicle side, the wires on the tank side of the harness may change colors, but it will be the larger 2 of the 4 wires. the 2 smaller wires are for the sending unit) If you have power at the tank harness, then its the pump or wires at the tank. If no power there, go back and check your switch, and wiring in between.

EDIT: The power will only be on for a few seconds when you first turn the key on to prime the fuel rail.. If the computer doesnt sense crankshaft movement(engine running), it shuts the power back off.

[GarygWatland]

I have the same problem with my 88 F 150

[bearcat329]

changed front tank fuel pump, works like a charm!
Rick, Ore

[t-genere]

gratz..
thats the same problem on my 86
damn things

funny thing is its the back one that doesn't work XD
oh well.

[rix444]

I have/had the same problem on my 95. Open the filler and listen for the pump. or lay underneath and listen. My front pump died and the rear works. When you hear one running, you'll know what to listen for. PS. You need someone to turn the ignition on and off. As stated, the pumps only run for 3-5 seconds, if the engine isn't running.

The fuel valve should be under the drivers seat, bolted to the frame. In my case it was only a valve switching tanks, not pumps. The pump wiring should come off the selector switch.