please have two problem with my 2002 ml 320 first my c d changer send a message that it is not install check all plug under set and behind radio no lights oh also c d changer,yes it has power does the amp under seat need to be check out and how do i do that help me please. my second problem are my door lock are not working when i start driving i really need help with my c d changer. oh by the way i have a radio that has a nav. system to replace the one i have in it right now