Fuel Gauge Stopped Working

[madmaxx]

disconnect the wires from the sending unit and and check resistance, shake the car back and forth so the gas moves the float up and down and see if you get a resistance change, this will tell you if the sending unit is working

[Blas]

Madmaxx - That's a good idea to try too. You can use an OHM meter to do this test if you have one...
Gil - Remember to also check the connections on the back of the fuel gauge since the problem started after you hit a few large bumps in the road...could be a loose wire connection there.

[GC427]

Blas & Madmaxx,

The fuel tank sending unit reading is 38.2 ohms (see attachment) with car at rest. When I rocked the car back and forth, the ohm reading increased to 41 ohms. The wire terminal connections on the back of the fuel gauge are excellent, no loose connections. The voltage stabilizer input reading is 12.32 volts (see attachment), and the voltage stabilizer output reading is 9.90 volts (see attachment). Although there is a resistance change across the fuel tank sending unit when rocking the car, isn't the resistance supposed to be much lower than these readings? Blas, I believe you indicated we should be looking for readings between 3 to 9 ohms. Also, when I turn the key on, I get a voltage reading of a steady 24 volts to ground from the brown wire at the sending unit, and a fluctuating voltage to ground from the green/white wire at the sending unit. I was expecting to see a nice steady 9.90 volts to ground at the supply side of the circuit to the fuel tank sending unit. At this point, do you think it's the fuel tank sending unit? With 38.2 or more ohms as a reading being sent to the fuel gauge, that would cause the fuel gauge to read empty. I think you indicated the lower the fuel level, the higher the ohm reading. Or do I have that backwards?

Gil