I have a 2010 Yukon with factory back up camera connected to the rear view mirror and the factory radio which isn't the GPS one. I just ordered the Avic-Z120BT and want to attach it somehow so that I can use the back up camera already on the car onto this unit. Hope that made sense. Not sure if the wiring harness will have all this stuff on there, asking now so I can order the needed parts before attempting the install. Thanks.