I'm in the process of adding a rear camera to my 2009 Challenger RT with the 730N nav radio. While the radio was out, and while it was on, I noticed that the radio's metal case gets very hot to the touch. Of course you wouldn't normally notice this when the radio is in the dash. I do hear a small fan running in an attempt to help with cooling but the radio gets so hot I'm not sure the fan does much good. Has anyone else noticed this when working on the radio? Is this normal?