Ray, with the situation as you describe, the problem pretty much has to be in the sending unit. Somehow the circuit coming in from the terminal for the wire has gotten directly grounded. Look at it carefully to see if you can see any broken fibre washers, etc., that would have the terminal stud in contact with the housing of the sending unit. If you don't see anything suspect there, the trouble is internal to the unit. I had my '57 unit out not long ago and measured the resistance, but had no reason to make a record of it at the time. Rats! Park Waldrop