Also use "The Club," it's a visual deterrent as well as a practical one. These vans are stolen for joy rides and are usually found when they run out of gas. Since there is no "chipped" ignition key they can be started with a screwdriver, so a kill switch will prevent that.  With visual deterrents these freeloaders will move on to an old Honda or Subaru.  

Ideally, you want to keep people from even considering getting in. For your parking situation get a camo tarp and throw it over the back seat and floor, then position this sign inside the van where it can be easily seen: https://www.amazon.com/DakotaLine-Warning-Bear-Trap-Sign/dp/B00ITVJMGU. If you want even more effect, splash some ketchup on the tarp. I doubt you'll have any further problems.

Stuart

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Christophe Guilbert
Sent: Wednesday, May 31, 2017 12:27 PM
To: vanagon@GERRY.VANAGON.COM
Subject: best way to install a killer switch

Hi,

I often park my Vanagon (camper 1983 air-cooled) in an area with a lot's of homeless in SF. Some times, parts which are hard to find "disappear"
on my van ! Well this is not life threatening and somehow homeless need
to make a living !!! ;-)   What would really upset me however would be
that someone steal my van !  I would like to install a killer switch which would make things harder to thief ! something smart requesting time to figure it out !

Any idea or experience ?

Thanks

Chris