To test the switch, temporarily disconnect the output wires and connect your meter (set to voltage) between a ground point and each terminal. You could also just use a test light. You really only need to test the "Run" terminal. It should be hot any time the switch is in the "Run" position.
If you don't have a ballast resistor, you may have reduced coil life, as it will be getting the full 12V across the primary circuit all the time, rather than just when cranking to give you a hotter spark.
