I have a Kenwood DMX706S in my 2011 Chevrolet 2500HD. I used to have it in a 2013 F150. In my F150 the factory backup camera would come on in reverse or when I used the Kenwood camera button. In the Chevrolet it only comes on in reverse. The purple white wire is connected to the Maestro unit. How can I make it work with the camera button and the reverse trigger like it did in the F150? I talked to Crutchfield tech line and they thought it was something about how the factory camera was powered being different between Ford and Chevrolet. I have been told I need to find and cut the power supply to the factory camera and repower it with switched power. Does anyone have any idea where I can make this connection under the dash?