Have the 1997 Villager, same problem. Did lots of trouble shooting, but finally found it in the headlight switch. To fix, remove switch from instrument panel (just pull), and disconnect from the harness. Remove the screws from the back cover and there will be 3 metal contacts. One was heavily worn and coated with black soot or plastic dust. I exchanged a good one for the bad one, cleaned everything with lots alcohol, and reassembled. All headlights working again.
Or you could buy a new replacement switch online for $75 to $150.