No, you are not checking it correctly. The sending unit is a variable resistor, it has zero ohms resistance at empty and about 90 ohms resistance at full. That is why, as the good doctor stated, if you have a break in the ground from the frame to the sender you will have infinite resistance and the reading will be past full. If you have a break in the sending unit tan wire anywhere it will produce a over full reading.
The fuel metering circuit is measuring the ohms in the sender, not sending hot full-voltage to the sender which could result in KA-BOOM!
If the gauge needle does not move at all [stays on empty] it is most likely a break in the circuit from the ignition switch to the fuel gauge.