I believe that they were probably there to decrease the vacuum effect that
occurs when salmming a door shut in a confined area.  Maybe it decreased the
chances of blown eardrums in the event that all doors were closed at once.

Mike G.

Rico Sapolich wrote:

> Another window question.  Does anyone know if the plastic vents mounted on
> the trailing ends of the rear side glass of '86 and newer vans serve any
> noticeable purpose?  My older Vanagons didn't have them and as far as I can
> tell the only thing they are good for is to leak a little bit of water during
> an intense downpour.  If they are not there to better my wretched life, I'm
> going to replace them with one piece side windows so that there is less of a
> C-pillar to block my view.
>
> Rich