Rattle in right ft or rear door

Is it a loud, heavy rattle like a door? Check both doors to make sure they are closed securely. Push against the doors from the outside and see if there is any movement, there shouldn't be. Is it more of a faint rattle? Does the rattle change at all with the windows up or down? Is there anything laying in the door pockets that could be rattling? Look for any screws on the door that may need tightening. You may have to take the inside door panels off and look inside the door. It could be the window hardware or lock linkage.