The sound would come and go when you struck a bump with the car. The dealer first replaced the rear left speaker sound didn't go away. The mechanic informed me he was surprised the sound was out of the rear speaker. He reported that they have been having issues with the front drivers door speaker. The door speaker problem he nformed me was due to either a bad spot in the wire harness as it passes between the body and the door or a transitor which goes bad that near the speaker. They checked all this and everything was fine. Finally I got angry one day and smacked the side of the dash near the radio. The sound went away. I informed the dealer who then rescheduled with me to look at the radio. The radio was ultimately replaced and the problem went away.