Re:  In '86-91 Vanagons the outside headlights have both low beam and high
beaam filaments

There is no application for H4 bulbs where both filaments light together on
high beam, except as noted when using flasher control.

This is true for USA-style "sealed beams," too.

H4 bulb life would be too short, otherwise, and it was never the design
intent for this bulb.

The only applications where low and high remain on together is when there
are totally separate bulbs for each, most often H7 bulbs.  These are usually
higher end cars than VWs.

Kent Christensen
Albuquerque
'81 Vanagon