Which color wire on the 2008 Silverado factory radio harness is ignition power?
 

I have a Kenwood DNX-5140 that I'm moving into my new to me 2008 Silverado. I'm looking at my install on my 2004 Silverado which I have right here and the red wire seems to go in an endless loop with only the yellow wire every being used as full time power from the battery. I don't see where I ever ran the red wire to anywhere but to every other red wire in the new system I had put in. It always worked and shut off with the truck but I'm lost as to where I found this info or why it worked without the red wire actually connecting to a supply somewhere. I never did find the reverse light and was too lazy to run to the rear for it.

Any advice or links would be great.

Thanks..

Gary