This was my symptom on my 2011 “2” I pulled the unit out and took it apart. On the top of the main board, really close to the output amplifier mounted on the side, there’s three large resistors that need resoldered. They crack their joints through the hot and cold cycles. Once they are resoldered, reassemble and reinstall in the dash. I didn’t remove the main board from the chassis box it’s mounted in, just removed the cd deck from on top and carefully unplugged the ribbon wire connecting it to the main board. You can leave the CD deck in place, I removed it so I could inspect other solder joints on the board. The three resistors are actually on the opposite side from the deck. Here’s a picture of the board and the three resistors. I touched up some other solder joints, but that was just preventative.