I need to replace the thing-mechanism-whatever you call it, that switches fuel supply between the main rear tank and the supplemental mid tank. Two hoses from the rear tank attach to it along with two hoses from the mid tank. Then two hoses go out toward the engine. It has one wire to activate it. I guess Barth installed it when they put the mid tank in. I'm pretty sure GM didn't install it because the mid tank is aluminum and I'm guessing from Barth. Would appreciate help. BTW, why would two hoses go to it from each of the tanks? My son-in-law, the certified airplane mechanic, doesn't understand it at all.
Jim

Jim,

Not sure any of this will apply to your set-up, but an in-depth discussion took place awhile back.
It's at:

http://barthmobile.com/eve/forums/a/tpc/f/3631087061/m/5451033022/p/1

Jim, can you post a picture of the valve?

You know, .........worth a thousand words?

Bill, I have a 6-port valve, 4 ports for lines going to/from each of the two fuel tanks and 2 ports for lines going to/from the engine fuel pump. I'm trying to get my mind around the need for lines going to the fuel tanks?? I guess that if there's excess fuel in the fuel pump, it drains back to whichever tank you're using??

I'm a little rusty on this, as my present P30 has no engine pump, but I believe the second trio of lines is for the vapor return from the pump to each tank. Without a selectable return that matched the tank selected, the wrong tank could receive the return.

BTW, the vapor return also returns some liquid fuel. I remember someone here had fuel returning to the wrong tank.