Classic/Antique Car Repair: gas guage 1971 Dodge does not work, electric fuel pump, jumper wire

Question
gas guage stopped working while car was stored and seldom started tank was near full  with original gas. car is original 1971 charger w/318motor no modifications. what is best way to diagnose problem?  if a connection, fuse  or float assy in tank or what what your help will be appreciated   this was grannys car when new and she drove it  til almost 90 years and commuted to work with it till age 79   thanks   art

Answer
If I was doing the job I would locate the fuel gage feed wire near the fuel tank. In this car there is no electric fuel pump so there will be one or two wires going over the top of the tank. One will be feed and if there is a second wire it should be ground and colored black. Cut the feed wire. With the key on and a volt meter connected to the wire coming from the front of the vehicle there should be between 5 and 12 volts present. No voltage with the key off. Now with the key off ground the wire coming from the front with a jumper wire. Turn the key on and the fuel gage should start to climb towards full. If it does the front part of the system is ok the problem is in the rear, a bad sender or a bad ground.
Brad