Have been dealing with annoying rattle for a year now. Rattles constantly when unoccupied.In and out of dealer service department. A Hyundai field service engineer inspected the seat and determined the internal hinge bracket cover is the cause of the rattle. Per Hyundai, the part has been discontinued and there is nothing they can do to fix it. Hyundai Consumer Affairs actually told me to contact the Auto Line Better Business Bureau. So I did. Waiting on a response, likely headed to arbitration. Anyone who has this issue and your car is still under warranty and Hyundai has failed to repair, Please file a complaint with the Auto Line BBB as there are hundreds of posts about Hyundai's rattling seats, yet no complaints filed against them so nothing ever gets done.