My truck has the dual tank but when I go to flip the switch it does nothing, is the switch bad or is the selector valve bad? I do believe I got the 6 outlet valve. When I go to the parts stores they dont ever seem to have a clue what I am talking about because they cant find it in there computers.

 

The valve on the frame has more of a tendency to fail than the switch. If you have a voltmeter or testlight, you could unplug it and get someone to flip the switch back and forth while you tested the wires to make sure.

 

Depending on your year, it may not be electrical and is operated off the Pumps output pressure.

 

He has a older diesel, so I believe the valve is electric.

 

I just replaced my whole system, two new fuel tanks, 6-port selector valve, and both pumps and sending units...what a pain, but I finally got it done. I got my 6-port selector valve from Auto Zone for about $60, not a bad deal compared to what Ford wanted. But you have to cut the factory quick-connect fuel line ends off and use brass couplings to rubber hose to install on the new fuel valve selector, AND you have to splice the 5 wires to the new connector as the ford connector will not work with the aftermarket valve selector switch. My only problem was the rear tank plug connection, I thought I had pressed it on completely. After I started driving the truck the rear tank pump worked but the fuel sender did not, I had to drop the tank again and press the plug connector FIRMLY onto the new pump assembly. Also, I installed a toggle switch into the oil pressure switch cutoff, so that I can turn the key to the "on" position, flip the toggle switch on and have either tank pump come on in the event that I run out of fuel. Normally if you run out of fuel with this configuration, the fuel pumps will not activate until there is enough oil pressure to switch the pumps on. So you end up cranking the engine for a LONG time to get fuel back to the carbs or efi system.