Hello I need help I have searched for hours I have a 2005 g35 coupe with Bose system I need to tap into the Ignition Wire not the acc wire this will be used to signal my Carnetix P1900 DC/DC power supply to turn on my car pc I'm working on.

1.What color is this wire?

2.Can I tap it from the back of the Bose HU

Thanks