When my vent is on the face setting, a grating/whistling noise emanates when the fan is on.This does not happen on the floor or defrost positions. The noise diminishes when it is in the face and partial floor or defrost setting. Any feedback on what may be causing the noise and how I could fix it is appreciated.
Something in the ductwork. Perhaps a leaf or, my favorite, a pine needle.
To fix it you need to get an “exploded view” assembly drawing of the ductwork (& dash). Perhaps you can find a way to get in there with a shopp vac and clean it out.
NOTE: get a manual before starting. Your passenger’s side has an airbag, and should you begin takung things apart without disabling the bag and it goes off…you don’t want to know.