[TBONE1964]

So you have a fuel gauge that has power, ground and a signal wire.

The power wire is the pink one and should have battery voltage with the key on. The signal wire will show voltage and that voltage will be resisted voltage from the sending unit depending on how much fuel is in the tank.

If you had the sending unit out of the tank and moved the float, it should change the voltage on the signal wire, which is the tan one. The ground comes through the cluster itself.

Can you tell me what the actual issue is?

Hope this helps,
Tom