car audio via aux issue

[Overcomer]

I have my droid plugged into my Kenwood KDC-HD545U head unit via the aux input. The sound work fine - blah blah blah....but let's say I'm listening to Pandora and arrive at my destination. I turn the vehicle off and unplug my phone and go on about my business. When I get back in the vehicle the head unit does not work....it has power, but there is no sound. I have to power off the vehicle again to get it to seemingly reset itself seemingly before I have sound again. I have checked/triple checked my wiring. The problem does not happen if go several times...off/on/off/on with just radio. I had the same issue with another head unit, and I thought it was the head unit because it was a cheap one. Can anyone offer any help? If it matters, the vehicle is a GM vehicle...TIA