When I turn on my newly purchased used 16 optima ex and the fan blower is on there is a loud fan like flapping noise, at first we thought it was coming from the vents but it is coming from the Panoramic roof right above the open and close button. When I opened. The sunroof, doors, windows the sound goes away. When I shut any of them the sound immediately comes back. Does anyone know what the issue could be, or if it is covered under warranty I have about 1 year left on the manufacturer's original 5 year warranty.