Now that the cold is arriving and the heat is being used, I notice a whistling noise coming from passenger side floor vent. It is pretty apparent when the fan is on the lowest or second lowest setting.
I can't tell if its the floor vent or the internal fan making the noise. But strange it only happens with the heat. Never had this in the summer with A/C.
I'll probably have it checked next oil change, but wondering if anyone else has experienced this?