On the passenger seat on the bottom side by the door there is a plastic panel with one screw towards the back and a inside clip towards the front. I found the clip unattached. I was able to re-clip it and hopefully I got the rattle. I try putting some felt there to deaden the sound and it work. But all that should be needed is for it to be clipped. My matrix had the same problems with clips that would come apart. The drivers seat is firmly attached.
Can you put that on picture 2 show it exactly...have also rattle over there somewhere...would be helpfull 2 see it where it's located... thx
Im not great with transfer of pictures. I will try to desbribe it better tell me if it works. Open up passenger door look at the side of the seat that faces door there is a plastic piece approx. 18' long and 4" wide move it or pull it to see if it seperates. The drivers seat is firmly attached. If you pull it out a little you can see a clip underneath that has to be snapped in place.
Did you put your hand on that plastic piece and does it move. Compare both seats. I will try tonight to take a picture if not.