Wiring two fuel tanks, solenoid, guage

Great Forum! I have searched the electrical forum and got close to the answer I am searching for but not quite. I am replacing the two rusted steel fuel tanks on my 1975 Starcraft Islander, one of which was disconnected. The new setup is this. The Two tanks feed to the back of the boat where a solenoid selects which tank to feed from. The sender on each tank is connected to a switch which has four terminals (1,2,3,4) which I assume feeds the selected tank's sender to the gauge. Terminal 1 goes to the gauge. In one position of the 2 position switch terminals 1&2 and 1&4 are connected. In the other position 1&2 and 1&3 are connected. I can't figure this out. What I would like to do is have one switch that would not only switch the senders to the gauge but also provide the 12v to the solenoid so that the gauge is reading the tank feeding the engine. Unfortunately, I am not the sharpest hook in the tackle box so would appreciate it if anyone could help me out with a wd and the type of switch that would do the trick.

Re: Wiring two fuel tanks, solenoid, guage

Here ya go. You need a two position, single pole double throw switch. This switch will have six terminals. It functions like two separate switches with one toggle. The three terminals on one side control switching of the senders to the gauge. Two terminals on the other side control the fuel selector solenoid. +12 volts to control the solenoid connects to the center terminal on one side of the switch. Either of the two remaining terminals will turn the solenoid on or off. How you wire this side will depend on how your solenoid works. With the switch in the OFF position the solenoid will be inactive which will allow one of the two inlet ports to feed through to the engine. With the switch ON the other port is selected. You need to match ON & OFF on both sides or the gauges will read opposite. So if you plumb tank one to the OFF port on the solenoid valve, then tank one sender needs to be wired to the OFF position on the switch.

Re: Wiring two fuel tanks, solenoid, guage

Thanks Silvertip. Your response was just what I was looking for, precise and clear. I have read several of your posts on other topics and you always seem to be right on target. Of course, your diagrams are excellent. Haven't had a chance to try out your graphic procedures yet, too many to-do's, too little time. Thanks again