Rally Dash Conversion Question

The gas gauge, the oil pressure gauge and the water temp gauge all need a path to ground to work even if they are getting 12v. The sender units provide this. For each sender, ground its attaching wire and if the gauge is working, this will peg the gauge, it is working! If not pegging, then there is a problem with the gauge, its limiter or associated wiring. If the only gauge not working then it is not the limiter.