dual tanks

[509lifted]

ok guys I have a 94 f250 with a 7.3 powerstroke diesel, it has the dual tanks and I have fuel in both but when I switch to the rear tank the gauge stays the same and doesn't switch to the back tank at all so I was wondering what it could be since Idk how to use a ohm meter to test the switch ned fixed by tonight if I don't have to order parts

 

[RonD]

Just off hand I would say the switch is not changing sending units, because the needle doesn't go high or low.

So remove and clean the switch or replace it.
If the rear sending unit was bad, then gauge would move when switch was changed, it just wouldn't be correct

 

[509lifted]

yea I took it apart and used more die electric grease with no luck so im gonna have to try a new switch

 

[adsm08]

Dielectric grease isn't a conductor. In low voltage (basically anything that isn't the iginition system) it will create resistance and keep things from working. For the tank selector switch you want electric grease.