what is the hole?

[Mrsteveoh]

theres a little hole in the bottom of the rear view mirror, im guessing its a mic?? but have no clue....if it is...how can i add bluetooth to talk on my phone handsfree through the car speakers and (if) that mic

[JumboBlack1.8]

I believe its sort of a lens that controls the auto-dimming function of the mirror......these cars were made a few years before BlueTooth blew up, lol

[Mrsteveoh]

ohhhhhh, lol okay okay....i was thinkin it was maybe for onstar or something like that, thnx man