# Mf 35 fuel guage hookup



## Ckinser1 (Oct 28, 2015)

2 questions first I just bought new guages for my mf35 project along with a new sending unit for the fuel guage. The fuel guage has three prongs plus the illuminator. I know one goes to the key switch and the other two go to the sending unit one being a ground. Anyone know where these wires go as the guage gas no markings. Second question does the fuel tank itself need to be ungrounded? I am replacing the rubber pads under the tank but I assume it will feed ground through the mounting bolts unless I add insulators under the bolt heads.


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## HarveyW (Sep 15, 2014)

I suspect the sending unit is isolated from ground? Otherwise, why would they have two wires? Use an ohmmeter to check for a circuit from each wire to the sending unit mounting base. From a picture of this type sending unit, it appears that the two wires are connected across the variable resistor.

If the sending unit is isolated from ground, hook power to your fuel gauge, and connect the wires from the sending unit. Lift the float and the gauge should read "Full". Lower the float and the gauge should read "Empty". If it reads backwards, reverse the wires. 

I've never seen a fuel tank isolated from ground. The rubber pads under the tank are for vibration/wear protection.


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## Ckinser1 (Oct 28, 2015)

Thanks I will give it a go


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