Need a Fuel Tank Selector Valve

[hatzie]

I'd give the pair of FV-1 valves a shot.

I drew up a schematic several years ago for installing the motorized valve with a minimum disruption to the original wiring.
It uses a pair of 5 terminal Mini ISO relays to convert the un-molested single wire setup to a motorized valve 2 wire system without modifying the dash switch or in-cab harness.
It's not a beginner wiring project.
You'd need to properly wire up 2 relay sockets and two tower terminals on the 6 position Delphi Weatherpack connector.
I'd recommend mounting relays on the firewall with the terminals down. The reason to mount relays with the terminals pointing toward the ground is... they fill with water in any other position and then stop working.
The main power connection should be to t̶h̶e̶ ̶f̶i̶r̶e̶w̶a̶l̶l̶ ̶j̶u̶n̶c̶t̶i̶o̶n̶ ̶s̶t̶u̶d̶ an ignition switched power source. It should include a 7amp Fuse.