Does anyone have a problem with a constant buzzing/ringing sound coming from their car when the car is moving? It is a very slight buzz that can be heard once the radio is off and the windows are up and it goes away once the vehicle has stopped. I thought it might be my speakers at first but the sound is gone once the car stops moving. Any ideas?

 

I only get that when I seem to turn the AC on now, but don't get it if the AC is off.