I just purchased my first Class C and we thought something was seriously wrong when the radio stayed on even though the ignition was off and key out. Once we realized that it's power source was from the coach/living area and not the truck we thought it was wired incorrectly.
Also, the screen flickers from bright to dark repeatedly and is very annoying. I've watched youtube videos, read the manual, and tinkered with the settings but no luck. The Axxera AVM70 seems to have a lot of good features and would be a great radio if I could just get it working correctly.