I am trying to get the gas gauge to work on my 36 1/2 ton. My old sending unit did not appear to function. I tested it with a multitester and got no movement in ohms when I moved the float. I have a new unit that does appear to work. Same process, ohms change when float is moved. New wire to sender and I am getting ohm movement through it. I have power to the gauge, but both gauges I have, one is original the other is nos I was told. No guage movement. How can I test the gauges with my multimeter ( I am somewhat electrically challenged) or another method to verify I have a good guage?
Thanks
Richard

Not sure on your car but the following usually works:

Disconnect the wire from the tank unit, and with power to the gauge, the gauge should read full. Ground the terminal on the gauge to which the tank unit is normally attached and it should read empty.