map light would not go off so removed it. light on top of cab would not go off, had to cut the wires and tape them for later, lights on radio go off randomly, oil pressure swings wildly, sometimes clickity clacking sound on startup, sometimes loses acceleration around 45 miles per hour,at low idle seems too sputter and yet left idling evens out. No heat after changing thermostat, water pump , reverse flushing the heater core with citric acid; drained coolent system but no sign of problems, if its the heater core etself, I am taking it out with a dremmel tool instead of taking the dash out. So, first question what about the electril, then the mechanical and third the heat in that order.

 

The switch for your dome light is located in your door handles as opposed to the old way of mounting a plunger switch on the A pillar. They go bad over time and cause the problems you're noting. Before you go and replace the door handle though, try soaking the crap out of it with penetrating oil. Lots of YouTube videos on it.