Actually, my passenger side vent doesn't blow (very well), and that's the problem. Vehicle: 2001 540i, 110k miles, all services up to date. Symptoms: Flow of air from passenger side vents only is very low; driver's side vents have good flow. Increasing the fan speed does not seem to have any effect. Closing driver side vents does not seem to improve flow on passenger side significantly. Also, problem does not appear to be affected whether the AC is on or not. The flow on the passenger side is just low all of the time. Question: Does this sound like the Final Stage Unit has failed or just a clogged pollen filter on the passenger side or something else? Thanks for any feedback/suggestions.