I had the vent motor tryign to adjust the vents on its own, once i unplugged the control wire plug to the motor the rotating noise went away therefore i found the culprit
take out the glove box, few screws and pop it out, u need to look down and there is a white plastic bracket, the 2 motors are there, there are 2 vent motors, mine that was makign the noise was the secodn one on the left.
hope this helps :s