I am installing a Sirius tuner/controller and have a wiring harness to power the unit that I need to power from somewhere (head unit, rear 12v). Does anyone know how to do this? I am looking for wiring colors/diagrams from the head unit on an 02 stock radio head unit. Any tech advice would be helpful.

 

In the factory radio harness, from a 2003 Cooper S here are the factory wire colors and there purpose.

White = Powered Antenna lead
White with Red Stripe & Yellow Dots = Steering wheel controls
Grey with Red Stripe = Illumination
Red with Brown Stripe = 12V+ Constant
Purple with Blue Stripe = 12V+ Switched power
Brown = Ground