I'm continuing to struggle with my headlights going out on their own
without warning.
I've replaced the light switch but that is not the problem as it didn't
remedy the situation.
It can't be the X connection because everything else works when the
headlights quit.
I took my Vanagon to my trusted mechanic but when he went to
troubleshoot it the problem would not duplicate.
Now I'm just driving daily waiting (hoping) for a permanent failure.
When the lights go out I can hold the turnsignal lever up and continue
to drive using the passing beams (which still will work just fine).
In a few minutes the headlights will come back on and stay on for
another day.
Anybody familiar with this particular situation?
By the way, the recent discussion on O2 sensors has been very
educational! I've learned a lot from that.

Jaymac,  87 Vanagon GL (2WD) 195,000 miles