Can't get the fuel tanks switch from one tank to the other?
Gas or Diesel?
There is a switching valve that is pressure operated mounted in the frame channel, if the fuel pump in the tank selected is not operating the fuel tanks selector will not switch tanks, sometimes crud will build up in the valve itself and stop the valve from switching. You need to verify that both tank fuel pumps run and pump properly, if they do then the fault is in the valve itself. I hope this helps.
Looking for a Used F-350 in your area?
CarGurus has 282 nationwide F-350 listings starting at $4,900.
Search Ford F-350 Questions
Ford F-350 Experts