I just removed my old gauge cluster that had dummy lights. I have two sets of new gauge clusters with actual gauges, one has and electric speedometer and one has a mechanical speedometer. My car has a mechanical speedometer but the mechanical replacement I have is in need of the plactic cover over the gauges.

I installed the one with the electric speedo tonight and just didn't hook up the sppedometer just to try it out. It appeared that the fuel, voltage, and oil pressure gauges worked but the tach an coolant temperature gauges stayed in one spot while the car ran and reved a little for about 15 mins. Fuel read full, oil pressure read over 60 and voltage read about 13 amps.

Does this mean that the other cluster won't work either and why wouldn't these gauges work? I thought for sure the tach would have at least worked.