My 05 x-type has this noise in the steering column or just to the right (if your in the car) of the steering column, it doesn't matter if the car is running or not, if the key is in or out, if the dome lights are on or off, i have no clue what it is but it makes this buzz/humming sound 24/7.

 

24/7?..No it don't, runs only for about 15 minutes once the doors are closed and the car is off...it is the HVAC cabin air sampling pump asperator..it starts as soon as you open one of the doors...

 

The intake vent is a little grille just to the right of the steering column on the bolster..make sure it ain't clogged with lint as that will make it sound louder.

 

I thought it was the Sirius receiver that the previous owner had installed, but I spent 2 hours pulling all that poo out of there and disconnectiong it. I went back to XM (1 day before the merger completed (doh!).

 

I popped the little vent you speak of off the dash and i see what appears to be a temp sensor or something, I don't see any lint or debris in there, would it be ok to shoot some duster in there?

 

What exactly does this little device do? I have never heard of one of the before LOL

 

Yeah I used the duster too to blow it out..

It sucks in cabin air for monitoring the temp and Humidity to adjust the auto featues of the HVAC.