What car do you have?
Is it a low volume, slightly metallic sound that occurs every time you drive over slightly uneven surfaces?
I have a TMS 100D from December 2017,
and have an annoying sound like the one described above. It sounds like it comes deep from the middle, or a little right to the middle, of the dashboard.
Tesla spent two weeks trying to solve it, and in the end gave up, with the explanation that it comes from the wheelsuspension, and is a design flaw on this particular version of the TMS, where the sound is conducted via the metal frame to the dashboard. They claim that can be improved a little by changing some hardware, but not removed. Hence I still have the sound.