So I have a 2013 cx9 and I started it when it was about 22° out and the air con/heat blower fan was completely off and I was hearing what sounded like a fan buzzing noise? Checked the circulation button, changed the blender settings, and even tried turning rear blower on/off as well as a/c and the noise didn't change at all. Just kept going and after a few minutes got quieter and about 10 minutes later it stopped...Can't figure it out.