Hi,guys drove my bmw x5,to the shops earlier,came back out ,started her up to this high pitched distorted noise coming from the radio,tryed the cd does the same,took the fuse out ,tryed again its the same ,very strange??,its the sat nav model,any you guys had this problem,? its so annoying!!!,sounds like somethings packed in or connection loose?? how do you get into the back of these units?