My new 06 has had an Air conditioning "Hummm" since it was new. 6,000 miles now. Since my Service dept is open Sat I decided to just run it by There for them to hear it. . There were THREE of us that just happened to drive in at the same time with the same problem. . Funny... Anyone else have this hummm??? It comes and goes but is not something "Cycling" really. More of a harmonic issue. Thanks!