I think I have the same problem, discussed on another thread here
I took out my (left side only) parcel shelf, and I still have the noise without the shelf or the US cover. It sounds higher anyhow, behind the tach and maybe a bit to the left. Looking up from below it appears that the "broken spring" metal-to-plastic buzzing noise is coming from something above the structure that supports from below. It looks like removal of the upper dash cover will be necessary.
Mine will probably be at the dealers next week for this problem. If I learn more, I'll post here.
If anyone has more information, please post it here. Please do not post here about the rear hatch, the mirror controls, the OBD II cover, etc., those are not this sound, this sound is from behind the tach, buried in the dash.