testing ralleye gauges

i was wondering how to test my ralley gauges. all i got to do is put a hot to one side and ground the other side real quick and see if the gauge starts to move correct

Basically yes...however you don't want to ground them out too long. You risk frying something out either you Voltage reg or the guage itself. Here is an article that will help you a bunch http://www.moparmusclemagazine.com/techarticles/interior/23241_instrument_gauges_repair/index.html