How is dual tank electric valve wired?

[Kurt Combs]

Thinking about taking the electrically controlled dual tank valve from a 77 F-150 and using it to replace the manual valve on my 72. Looks like it just has a single wire going to it which seems odd. Anyone know how they are wired?

[SmoothJ69]

I don't know specifically how its wired but if there is only one wire then presumably that wire provides power to move the valve to the other tank (and no power to it leaves it on the standard tank) and its probably grounded through its mounting points.

[Kurt Combs]

That's what I was thinking, but it would draw power all the time, which seems like a bad idea???

[SmoothJ69]

It would only draw power when the tank is switched to aux and the truck is on. if the truck isn't running, who cares what position that valve is in and I would assume you'd want it to "fail" in the main tank position. of course I'm making assumptions in how it operates.

I know I've read that some model F trucks actually have fuel pumps in the tank and the switch just chooses which pump gets powered..I've also read that the valves all fail quite frequently so it might be better to just buy a new one, from what I gather they are stocked by ford dealers. You could also just buy 2 electric fuel pumps, bypass the mechanical one on the engine and switch between the 2 for which tank you want to run.

I suppose if the 77 is (mostly) complete and you can get power to it, you could just throw a multimeter on it and see what happens when you change the switch.

[fmartin_gila1]

At one time in the past, I owned a 79 F250. It had the 1 wire valve. The dash switch was a dual purpose in that it changed the gauge circuit from 1 tank to the other and at the same time it sent power to the valve. So when you switched it to Aux, it switched the gauge to the aux tank and powered the single acting valve to open the port to the aux tank and closed off the port to the main tank. The valve is spring loaded to return to the main tank position when power is removed. It is grounded to the frame by the mounting bolt. There is no power to the switch when the ignition is "off".

Fred

[Kurt Combs]

Thanks for the posts. I am trying to determine if I want to go with the electronic valve or stick with my manual on the floor version. It is really hard to move the handle on the existing valve, but I can completely shut off the fuel supply when working on the engine, not an option with the electrical version. I will look into rebuilding the original valve, or finding a replacement. I am going to add a sending unit to my second tank, just how that is wired is what I am thinking about, and of course, should I swap the valve at the same time.