Perhaps I have the 'fuel gauge wiring concept' wrong in my head.
I would envision ground being at the gauge end of this circuit.
I picture the fuel gauge as being essentially a 'resistance meter'.
I would expect current to flow from the gauge, then through the sending unit, where the sending unit applies a certain amount of resistance (depending upon fuel level), then back to the gauge which measures this resistance, then to ground.
Am I on the wrong track?
1986 300E 5-Speed 240k mi.