I have a 2006 Vanden Plas. The right-side rear view mirror is supposed to dip down when placing the car in reverse to aid in parking. Mine is intermittent. If the window is down I can hear the little motor make some minor noise. Sometimes it will dip down and then not come back up when the car is placed in drive. The motor in the mirror works fine with the adjuster control on the driver's door. Anyone have any ideas?