hi all i have an issue that has happened very recently my internal heating vents dont seem to be opening correctly when im selecting either vent for the air to blow out it does not seem that powerful ive dropped the glove box (A3 18T sport 98 plate) to see if i can hear the vents opening and when its on either selection i can hear the air blowing but the vent stay part closed as i can hear the air whistling past it ive run a ecu check and no codes come up any one any ideas ?