My truck has the tank switch valve, but only 1 tank, how do I make gauge work?

[1976Scottsdale]

My truck had dual tanks at one point and now has only 1 tank, but it still has the switch valve.  It is the one with a lot of wires running to it.  I am wanting to make my fuel gauge work, what wires do I need to move around and what colors are they?

[VileZambonie]

All you need to do is flip the switch. Are you saying if you eliminate the switch?

[stevens]

The sending unit is on top of the gas gage so just run it straight to the one gas tank

[1976Scottsdale]

My truck has had parts swapped here and there, so it no longer has the tank switch in the cab, nor the wiring for it I think, but the wiring and parts are still on the frame.  I am just wanting to find out what color the wire is for the fuel gauge, the last one I did was pink or red, so I can run a jumper wire to the tank from the splitter valve and make the gauge work.

[DirtyLittleSecret]

OR
you could invest in another gas tank/switch! 
My wife calls it her insurance plan...another tank to tap!

[1976Scottsdale]

My wiring harness in the cab is not original to my particular truck and does not have provisions for the tank switch.

[DirtyLittleSecret]

Ah, now I got it.  Sorry I dont have a quick/easy answer for you . 
Is there anyway you could do a Painless Wiring fuel wiring kit (dedicated/closed)?  That's what I'd check into at this point.