Every aftermarket radio I've ever installed had 2 power leads; one smaller
lead to battery + to keep the station presets and the clock time, and one
for accessory switched power + for the main radio's power.

I've never seen one with a 'signal' input to trigger it on and off.

Mike B.

----- Original Message -----
From: "Mike S" <mikes@FLATSURFACE.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Saturday, February 09, 2008 4:13 PM
Subject: Re: lighted switch needed

> At 03:02 PM 2/9/2008, Scott Daniel - Shazam wrote...
>>Thanks for the reminder on that.  I haven't done it but as soon as I
>>read
>>about it here, I thought that's the perfect solution, using the key
>>buzzer
>>signal from the ignition key to allow power to the radio.  ( use it to
>>control a relay of course , not actually supply power to the radio ).
>
> You should be able to drive the radio's "acc" lead directly. Every car
> radio I've ever dealt with draws it's working power from the battery
> lead, and just uses the accessory lead as a signal - not drawing more
> than a few mA from it.
>