I ran a few searches, but kept getting hundreds of threads. The ones I read were about repairing or troubleshooting them.

I got this crazy idea of putting dual tanks on a truck. I know where to mount both tanks (I think) and which will fit in there (again-I think). More research and final measurements will be needed still. They will have the factory sending units and pumps in them (will be used).

I wanted to find out "how it works" before I go a lot further into research and locating parts.

How do the factory installed one work? My dad's 88 f-150 has a flip switch that goes from one tank to other (gas guage reads whichever tank you are on).

I am guessing both tanks feed into a control valve somewhere? The dash switch controls a relay that moves the valve and changes the electrical circuit to the guage?

Where are these things mounted typically? Anyone have a wiring diagram/fuel circuit diagram or know where I can find one?

Any help would be appreciated. I truly know less than nothing about these.

Thanks everyone,
Brian