There was a new alternator installed, now on hte harness we can only hook up one of hte wires, what must we do to get hte gauge working?

An original gage or an aftermaket volt gage? Replacing the alternator shouldn't have affected the original wiring.

original SS gauges, well, i think my dad said that it no longer has a regulator, so that is leaving us wiht an extra wire and a non working gauge.