It’s been discussed on here before with a longer thread. Not sure what to search for though. FWIW I had the same problem when I bought my car 5 years ago. It only seemed to happen when I had my ac/heater on 0. When I have it set between 0-1 I’ve never heard that sound again. Maybe try that as I think it might have something to do with the ventilation. Mine was more of a high pitched sound though. Use the search function and you’ll more than likely find the thread I’m talking about, and it’ll have more updated info than this older post. Just make sure you see the date before posting. A lot of the time these members are not active anymore.