Fuel Gauge not working

[ben23f]

Hi everyone,

my fuel gauge is not working for some reason. All of the other gauges work so i'm not sure what is going on.
I have pulled the float from the tank and measured the resistance. As i move the float arm, the resistance changes so that seems ok.
The fuel gauge is powered by a short wire that comes from the water temp gauge.
I measured the voltage going into the water temp gauge it is about 11.5V.
I then measured the voltage going into the fuel gauge (from the water gauge) and it is only about 6.5V. Could this be the issue?

Otherwise i'm not too sure what else it could be. The tank seems to be earthed well, and i have checked and cleaned all connections in this circuit.

Any suggestions?

Thanks

[faux40]

All three gauges (fuel/oil/temp) get power from the same source so all three should have the same voltage -- Around 12v at the IGN terminal on the gauge -- 11.5 seems about right. Then the second connection on each gauge goes to the appropriate sender, then to ground. It's the variable resistance inside the sender that moves the gauge. That sounds like your problem may be at the voltage source. I'd suspect the connections between the three IGN terminals.

John

[RiverPatrol]

Starting around '67 there was an external regulator for some of the gauges. I think it was only for the oil and temp gauges, but it may have included the fuel gauge as well. There was never a good wiring diagram for it, that I could recall finding. I'm not sure, but it might have changed to an internal regulator within the cluster at some point.

You might also check to make sure you have continuity from the sender to the gauge. The is a connector that the fuel gauge wiring goes through, near the starter. Make sure the connections are good. There might even be a break in the wire somewhere.