Most modern cars do this. Not only the radio, but power windows and
sunroofs will work until the drivers door is open. It can be done with
either a latching relay or a relay wired with a "holding" contact.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
Of Robert Fisher
Sent: Friday, March 24, 2006 8:35 PM
To: vanagon@GERRY.VANAGON.COM
Subject: How is this done?

I was driving my step-dad's Cadillac and it has an interesting feature
that made me think of the recent thread about wiring the radio through
the ignition switch. Say you're driving along listening to the radio and
you stop and park... you turn of the car and pull out the key, and the
radio stays on- until you open the door. It shuts off when the interior
lights come on, so the trigger is obvious I guess, but how the rest of
it is done, I don't know. I have no idea at this point if it's a feature
of the particular radio, the car or if it was a trick that the
installers rigged up. The radio isn't hot-wired in the normal sense- you
have to turn over the key as normal to get it to come on. It has the
power antenna and memory wire if that makes any difference.
I will find out if it has anything to do with the car, but I don't know
what I can learn about the other two things. I haven't really given it
much thought at this point but I'd like to figure it out. Any ideas?

Cya,
Robert