I suspect a poorly-placed wire in the dome light circuit has chafed through its insulation, providing a short to ground. There's no easy way to find it. I'd check all the domelight bulbs for a broken bulb, but you probably won't find one. You'd want to find the appropriate wires in the wire harness and follow them along, from fusebox to light module to door switch to light (YMMV), looking for bare copper. That's going to mean pulling trim and upholstery, maybe even pulling the door trim panel. Ugh.
To tell the truth, I'd trade it with that fault and let the garage deal with the hassle of finding the short.
Yeah, it's pretty much out of our expertise, that's for sure...it's an Aerostar and it's very hard to work on.
I imagine we'll get it fixed and then try to sell it.
Might want to check the domelight socket itself for damage causing the power wire or terminal to short to ground.
Also, bulbs have been known to short out without glass breakage. I had that happen to a nightlight bulb in my house, it tripped the breaker.