AIR struggles after driving
 

My AIR conditioning on my 2001 X5 blows nice an cool, and strong for about 20 minutes when driving...then slowly start becoming less of a flow through the vents, though is sound like the air so blowing, but staying in the dash...still loud blowing sound. This symptom seems to happen quicker when jumpping right onthe freeway, as opposed to city type driving.

If I park the car, let it sit for an hour...then drive again, AIR goes back to normal...until I continue to drive a significant time. I have tried depressign the MAX AIR, but does not eliviate the issue. I also notice a "chirp" in dash\vents as the issue is happening. I do not hear it when air is blow normally?

Re:AIR struggles after driving
 

Could this be something to do with heater fan??

My bet is on the evapotator freezing up.

Any suggested solution to such an issue?

Most likely needs an evap temp sensor, or has a leak in the evap case near the sensor throwing off the temperature readings. It may take a proper diagnosis to nail down the full cause of the freezup.