2014 Renault. I bought it almost new and didn't have this issue.
When the heat is Off I can hear a rattling/vibration noise that comes from the inside of the driver side's air vent. It doesn't happen when heat is On.
I have no idea of what the cause of this is. It only appears when I'm driving, and it intensifies on rugged asphalt and streets that are on bad conditions. I don't hear this noise from the other vents.
Is there any way to know what this issue could be?, should I fix it by myself or take the car to the workshop?