Thread:

dual fuel tank wiring diagram/ help

Originally Posted by matt1840

My buddy and i are having trouble tracing down trouble with the fuel systems wiring.. We know the gauge works but unsure if the senders are any good. we traced back all wires and found some that have been cut and just dont make any sense. Is there a way to test the sending unit while in the tank or must it be removed... And does anyone have a simple giagram of how to run wiring for dual tanks to a single gauge... For some reason one tank feeds faster than the other so a switch needs to be wired in to check level of both tanks..

A switch has been pre wired into the boat from past owner but from the looks of it, its never worked..

The sender should read about 30 ohm empty, and near zero ohms full. You only need to switch the sender wire between the tanks, be sure the senders are grounded, or they won't work.

Sleek,

Here is a diagram of what we have. We weeded out alot of useless crap and came up with this. We can switch between senders, but even with the tanks 1/4 full we always get a full reading on the gauge for both tanks and an empty reading in the neutral position. My guess is im switching over a full 12v to the gauge which is giving me this outcome.. Do you see somethin wrong? I dont really see both senders being bad... or maybe??

I see the problem.... on the guage there is (I) ign, (S) sender, and (G) ground. The (I) goes only to the ignition, the (S) goes from the guage, to the center tap of the switch, and the (G) gets grounded. Now from the switch, your left and right sending unit wires attach to the throws of the switch. There is no need to switch the grounds thru the switch. Hope this helps

oops i did forget to show the wire leading to the ign from the gauge.. but it is there. should i switch it up to a single pole double throw switch??? (3 prongs) sender wire from gauge to center prong on switch and a wire from each center pole on sening unit to each side of switch? i understand that the grounds dont switch just the "hot" wires per each sender.

possibly draw up a diagram to show just incase im not following you?

well, it aint pretty but here it is.

the only reason i can think of to bring a ground to the switch is if it has a light in it. in that case you would bring a hot from the switch for your dash lights over to it. that part isn't shown here.-jas

cool.
so, what did you draw that little scetch with? kinda cool. being an electrician i should have something like that,lol.

I'm not an electrician, and am basically clueless about wiring and electrical stuff. So my question is, what is a single pole double throw switch? Is it a two position (on-off) type switch, or a two position (on-on) switch, or is it nether of these and something completely different like a three position switch? Can I see some pictures, and where can I get them?

I am getting ready to do my fuel system and have do idea how to it. I am going to start a new thread on the entire fuel system rigging; plumbing, wiring, filters, pumps, all the stuff that goes into rigging a proper fuel system for dual tanks.

Sorry about the thread jack Matt.

Thank you.