I have a 2010 Challenger SE with the "nothing special" radio. CD\Sirius\AM-FM\Aux. The last couple of days, when I start the car, I get no lights from the radio for at least a couple of minutes. Then it comes on and all is well. No particular time, it just happens. This occurs sporadically. Any ideas on what this could be? Pushing on\off does nothing until it's ready.