I've done it on 84's and up, it may work on all Vanagons though.

The grey wire powers the "you left your keys in the ignition"
buzzer/mexican hat dance when you open the door.

By wiring radio this way no stress on the ignition coil ECU etc as
you would with key set to ON position but engine not running.

>What year did that start Paul?
>
>On Thu, Mar 27, 2008 at 10:03 PM, Paul Guzyk
><<mailto:paullist08@guzyk.com>paullist08@guzyk.com> wrote:
>
>I've used the Grey/black wire from the key switch for radio ACC power.
>
>It's +12V whenever you INSERT A KEY into the ignition, no need to
>turn the key.
>
>when you remove your keys, radio goes off. This way you won't
>accidentally leave the radio on and drain your battery.
>