odd electrical problem

I have a 94 dodge spirit 3.0, and for some reason one day the tach, the dome
light the radio and the cigarette lighter quit working all together,
sometimes at no certain time they will work for a short period of time, I've
checked all fuses none are bad, I've checked the engine ground to the body,
I have even used an electrical meter to test for 12 volts at the radio
power, it has constant power, but no power when the ignition is on, what
could be causing this?