74 dart can’t get a spark

Ok so just cleaned bulk head terminals and plugs going into it and still just cranking when I turn the ignition. The ignition coil and the ballast resistor jumps from 15 to 12 to 5 volts on my meter for some reason but stays on 12.8 while on battery terminals. Next stop is the steering column connector.

Could the ignition switch be the problem even if when I turn it the engine cranks?

Thank you all for the help. If anyone lives close and wants a beer or a Diet Coke I’m down to hold the flashlight and learn or you can hold the flashlight and mumble under your breath in disappointment like all the car dads hahaha