It started a few days ago. It sounds like a hard drive spinning constantly and it can be heard while driving and it's very apparent as it is louder than the A/C or any other sound the car makes while standing still. I've tried rebooting 17" and drivers/center display and trying to "power off" the car through settings. Nothing has affected this issue. As I have not been able to charge the car at night or at all since I need a new UMC (picking it up tomorrow at the LA service center) I'm not sure if this issue and the bad UMC are connected in any way. After calling TM they said the car has not reported any errors and they are not concerned about driving it 130 miles into the service center.