The switched power line on most modern stereo units IS designed for only
signal-type currents; i.e., to tell the main power line to stop
supplying current the illuminated faceplate, etc.  All large current
draws go through the unswitched power line, which is why it is a much
thicker wire than the switched power line.  I recently hooked the
switched power wire on my new panasonic unit via a vampire connector
directly to the key-in-ignition signal wire, and there have been no
problems at all.

David Beierl wrote:
> At 12:22 AM 2/24/2009, Gregory Smith wrote:
>> The Vanagons also have a second, better choice in wiring a stereo to
>> a switched source; it's the "key-in" wire from the ignition
>> switch.  Hook your stereo non-memory wire to this wire, and the
>> radio will work anytime the key is in the switch, not turned on,
>> just in there.  And a paper clip even works in a jam.  This way, you
>> pull the key and the radio turns off, and you can also listen to
>> your stereo if you're doing other things in the van, and don't want
>> to have key "on".
>
> I'd strongly suggest using that as a signal to drive a relay -- like
> all manufacturers, VWAG is a pennypincher to and beyond reasonable
> limits (twenty-gauge internal wiring?  Please!  DIN themselves say it
> should be at least 18-ga for mechanical reasons).  I seriously doubt
> they built that switch to handle more than signal-type
> currents.  That might have cost another five pfennigs per vehicle,
> and that ain't hay when you're building millions.
>
> --
> David Beierl - Providence RI USA --
> http://pws.prserv.net/synergy/Vanagon/
> '89 Whitestar "Scamp"
>