Check its not rain dripping down the back of the speaker from the door seal design, which I have to say is absolutely crap, rain runs down the door glass to seal at top of door, then to the end where it meets the mirror, then goes through a small gap there & drops through the door out the bottom, all that time drops supposedly down past behind the speaker, unfortunately thats not the case all the time by my research or they maybe just plain crap speakers,