so if the gas and temp gauges don't work...

Sounds like you need a wiring diagram. If you studied the copper trace on the back of your inst' panel you should find the same 12 volts that powers the voltage limiter also powers a couple of lamps at right upper corner. 73 panel is my reference though. 72 may not be identical. 12 volts goes to the middle leg of the limiter. Ground on one side lower pulse current on other side. The middle slot should have a 2nd male terminal poked in there too that comes from the noise suppression cap'. if that is left out connection could be lost.