F150, dual tanks, no gas, help please.

So I have this 86 F150, 4x4, 302 EFI, with dual fuel tanks. I am not getting any fuel to the fuel rail, thus, does not run.

Here's what I know. The fuel pump relay does energize momentarily when the key is turned on. The front fuel pump runs. Each tank has it's own, low pressure fuel pump inside. No matter which tank I switch to, I hear nothing running in either tank. About hafl way between the forward tank and the front fuel pump, I see where both tanks feed and return lines merge to a single feed line to front pump and fuel return line from the pressure regulator. I inclinded to think that is the tank switching valve. I do not see any electrical connections to this "switching" valve. I was assuming that it may switch itself, based on which tanks pump is feeding it. (Assumed) It seems odd that both tanks pump would go out seemingly at the same time.

I was wondering if anyone has any diagrams of this fuel (tank) system or links to such. Diagrams of the electrical and component layout would be real handy. I hooked up to the test connector and can trigger the fuel relay and jog the front pump, but no action from the tanks. Wonder where the switching relay might be for the tank pumps and/or if the same output of the relay that starts the front pump powers the tank pumps. If my dash switch is not doing it's thing properly, might explain the second tank pump not runnning. It does seem that the fuel gauge switches from tank to tank.

I have a 94 f-150 with dual tanks and if you togle the switch like you are going to switch from one tank to another but stop half way it will shut both pumps off.You might want to check and see if you're switch is bad or if you have a blown fuse in the fuse box.

Funny you mention the selector and fuse. When it would not start, first thing I found was that the fuel selector fuse was missing. I out a fuse in there, but it made no difference. I can't imagine why the fuse was missing or if it was ever there. This is where a wiring diagram of the fuel pump/tank selector system would be real handy. I'm currently changing a tran in an Explorer, but soon as that is out, I want to push the F150 back in my shed and dig into the fuel delivery problems. A diagram would save much time.

Given your reply, I will probably start at the switch. That might seem to be somewhere in the middle of the circuit.

Right, since the selector switches power to the correct pump, if the switch is bad, neither will get power. Check for power TO the switch when the main pump is running momentarily with a test light. If you get power in, and none out you just found the problem. However, it's not a common failure. The ground circuit for the in-tank pumps is shared, so if you lose the ground, neither will work.