I just realized that a static buzz is coming from the little speaker in the passenger-side b-pillar. I have had an after market head unit for a while with no noise, and it just started. Any idea of what this speaker does? I can't imagine it is tied into my head unit? Why would it just start buzzing? I have OnStar...is it tied in with that? Car didn't have a navigation system?

Your thoughts are appreciated. Thanks.