Instrument Lights Not Working

Thanks. I'm getting a "grocery list" of things to try.

I'm never insulted when people ask if I have tried this, or that. It never hurts to ask.

ONE MORE THING.... I have heard/read about INSTRUMENT VOLTAGE REGULATORS. I don't recall the 1966 Barracuda having one. Am I wrong?

If my car had one, it must have fallen off before I bought it. IF it is supposed to have one, where does it plug in? I don't see anything that would suggest having one.