Fuel Gauge not working on 57 Bird

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AtlantaTBird1

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Bronze Member
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Jan 20, 2018
Thunderbird Year
2002
Hi All. My father has a 57 Bird, all original and in Rose Pink. He's very proud of this. However, he's having some issues with the Fuel Gauge. The fuel gauge works when you ground it. By this I mean the power is sent directly to the gauge. The sending unit is brand new. However, when the gauge is hooked up correctly, there is no reading on the gauge. It just sits on empty. Any help would be greatly appreciated. Thanks. Tom
 
Have you tried it with the sending unit out of the tank and moving the float arm manually?
Jim Yergin
AtlantaTBird1 said:
Hi All. My father has a 57 Bird, all original and in Rose Pink. He's very proud of this. However, he's having some issues with the Fuel Gauge. The fuel gauge works when you ground it. By this I mean the power is sent directly to the gauge. The sending unit is brand new. However, when the gauge is hooked up correctly, there is no reading on the gauge. It just sits on empty. Any help would be greatly appreciated. Thanks. Tom
Click to expand...
 
Is the temperature gauge also malfnctioning? You could have a problem with the constant voltage unit. There is not much to that wiring circuit. Power comes from the ignition switch through the constant voltage unit and feeds both the fuel gauge and the temperature gauge. (wire is black with a green stripe) Then from the other side of the gauge it feeds all the way to the sending units. (yellow wire off the fuel gauge - red with white stripe off the water gauge for water temperature) There is one connector between the fuel gauge and sending unit (float). I would take a voltmeter to check input and output at the constant voltage unit. (I think it's 12V in and 6V out. I could be wrong about that but it should be a constant voltage and I'm pretty sure it should NOT be 12V out). Next I would check continuity of the wire from the gauge to the back of the car (I wold unhook the wire at both ends) Lastly I would take an ohm reading off the rheostat on the fuel float. You should be able to find the problem using this approach.
 
I would check where the sending unit came from, my understanding is these are hard to come by. Replacements require new (non matching) fuel gauge thereby bypassing the constant gauge voltage unit.
 
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