The stock radio/cd player in my wife's 2005 Sierra quit. The radio still worked but the cd player was hit or miss. So I bought her a new aftermarket radio/cd player and installed it today. I used an aftermarket harness so it was a fairly simple installation. Anyway, now that the radio is installed and all buttoned up, it won't even turn on. No power at all. I assume the problem is some kind of security issue. What do I need to do to get the radio working? Is there a simple reset procedure? Thanks!!