I had this problem once. I found the solution was to press and hold the "On" button for more than 15 seconds. That shut of the radio. I haven't had it happen again.Hi guys,
2016 Metris Cargo radio will not turn off by key or button. Had to disconnect battery over weekend. My dealer has no idea as well. Metris in service garage @ Mercedes till we find out why. Anyone else had this problem?