But is disconnected.
You can use it to trigger the radio power, but you have to disconnect it from the delay timer (on late models at least) and run one white wire to constant (+) power, the other white wire to the radio trigger (usually a small gauge blue wire).
I like doing this, it means the radio has power if the key (or paperclip for that matter) is in the ignition, take the key out and you can't "leave the radio on". Good for us older forgetful types (did I just say that?).
Gregory Smith

'87 Bertone X1/9 Corsa
'88 VW Vanagon
Olympia, Washington, USA