Tractor Repair: 135 fuel gauge not working, mf 135, fuel gauge

Question
Hi,
I have a 1964 MF 135 and fuel gauge not working gauge is brand new. I have heard that it may be the Dynamo or the control box. Any advise would be graetly recieved.

Answer
  The sending unit in the fuel tank may be bad, there may no power to the gauge, or there could be a problem in the wiring between the sending unit and the gauge.  Attach a ground wire to the center terminal of the sending unit with the gauge wire on it, and ground it to the tractor somewhere.  The gauge should then show full.  If it does, the sending unit is bad.  If it does not, check the wiring between the sending unit and the gauge, and also check if there is power to the gauge.