Bingo!
I think it's fixed...
The two ground wires coming from the headlights had fused together
because they had
been squeezed together into one connector at the ground under the dash.
The two wires had formed a  one-inch melted 'Y' shape coming from the
ground crimp connector.

I split them up, each with their own (high temp) crimp connector...
I hope this is all that is was!

Joel Walker wrote:

> try jumpering around the contacts on the headlight switch ... that
> would be my first guess (the switch), as they have a history of going
> bad.
>
> next guess would be a bad ground wire under the dash, particularly
> over above and to the left of the fuse box, at that gaggle of brown
> wires on that multi-connection plug-thingie.
>
> after that, i'm afraid i'd suspect the fuse box. :( but vanagon fuse
> boxes aren't particularly known for failure ... although it could
> happen (internal crack or something).
>
> good luck!
> joel