Got any ideas how to fix a squeaky backrest (it's not from the seatbelt)

 

If someone sits on it doesn't squeak anymore but in the rest of the time it's very very annoying.

 

This issue drove me crazy for months. I took the car to the dealer, who heard the sound, but couldn't fix it. After searching this board and some others, I decided to tackle this problem myself. I completely removed the rear seat bottom. This is easy, just reach your hand under the front of the seat and pull. After removing the bottom, I jammed carpet padding between the rear seat cushion and the back wall of the car. My car has been silent ever since!!!!!!!!!

Now, I have a small rattle coming from the area near the window controls and door locks. Any ideas on this one?

 

Wind your window down fully when the door is open, then wind it up, and close the door. If you have a squeak rather than a rattle some people have found silicone to work. (Search some of the history on this board).