I heard the noise in my X5 a couple times. It's like a relay type noise in mine and reminds me of a click clack like something moving one way, then back the other way.

Best way to address the noise is to crank up the Premium Sound System and jam to your favorite tunes! All joking aside, this new car has all sorts of new noises. Not sure why BMW thought it was ok to design it this way but it is somewhat annoying.

I have to jump in the trunk and have hubbie drive in our neighborhood to isolate the sound. He says I have bionic ears, otherwise I'd drive. If I find anything, I'll come back and post.