Need help wiring fuel gauge

[philt]

I bought a used boat with a built-in fuel tank. The fuel gauge (Tempo brand) is not working. When I switch the ignition on the gauge immediately pegs on empty, even though there is fuel in the tank. Disconnecting the sending unit has no effect so there must be a short or open somewhere, but the boat has been rewired and worked on many times so it's hard to trace wires. <br /><br />Can somebody tell me how the gauge / sending should be wired ? The gauge has three terminals, one labeled "gnd". But the "gnd terminal is wired to the positive side of my system. Thanks for any help.

 

[petryshyn]

Re: Need help wiring fuel gauge

Sounds like you have a balancing coil gauge. One lead should go to ground, one goes to accessories (live with key on)and the last one goes to the tank sender. The tank sender usually supplies a variable ground for the gauge. I would use a test-light from a good ground to the lead at the sending unit(with the gauge lead still connected). If the gauge deflects, then the problem is in the sending unit, or the GROUND for the sending unit. If the gauge doesn't move when you install the test-light, then the problem is in the gauge or the wiring to it. Always use a test-light when bypassing the sender, or you risk damaging the gauge. Seems awfull strange that the grnd. terminal is connected to battery positive.

 

[dmessy]

Re: Need help wiring fuel gauge

I experienced the same problem with my 5 year old boat and found the sending unit's internal float was all rusted and mucked up( so was the fuel tank)It was unable to move from empty freely. Ended up replaceing the whole tank and sending unit.Good luck!<br />My .02$ worth...

 

[philt]

Re: Need help wiring fuel gauge

Thanks dmessy. I removed the float/sending unit expecting to find what you describe but mine looks great. The tank interior and float unit look like new.