I have this in my 1984 westfalia and have always wondered what it goes to
> and what it is for. Thanks
>

Silver Socket, AKA  "BMW Socket", AKA "Powerlet plug".

http://www.google.com/search?&q=bmw+power+motorcycle+socket

I have a three-way portable gas absorption cooler/fridge unit that for 12V
running has a cigarette lighter plug that converts into a BMW/Powerlet plug
via removal of a plastic sleeve. I've long been tempted to order a socket
for it because the cheap FLAPS cigarette lighter socket I have scabbed
behind the passenger seat gets as hot as a branding iron from the amperage
that 12v heating coil draws. It looks like the Powerlet socket should handle
more amps, but I'll be darned if I can find a definitive rating or find
anyone else who has a Dometic RC3000 cooler and has used one.

Eh. I haven't bought anything Vanagon this week. I'll quit being a
cheapskate and buy one now. When I find out, I'll add it to the silver
socket article in the VanagonWiki... errr... hmmm.

--
John Bange