Automatic Recirculation Sensor Replacement
 

Does anyone know where the sensor is for the automatic recirculation? On my second X5 that feature does not work. Anytime you are behind a smoky vehicle the recirculation does not change automatically. I think the part is this
http://realoem.com/bmw/showparts.do?...00&hg=64&fg=45

But I still do not know where it is. I would like to try and clean it before I go to the dealer and get a new one.