In the past several years, I have been living with this awful musty odor whenever I turn on the heater or AC. It is sporadic and unpredictable as to when it starts and how long it lasts. Other people also complain about this problem online, and I understand there is a class action suit against Mercedes in Georgia regarding this issue. My car was garaged until 2013. During that time there was no such smell problem. It started after we started parking the car outside.