Air Conditioner not working

[trashheap]

I have a 2010 X5 35D E70 Diesel that the A/C stopped working a couple of weeks ago. I can push the A/C button and it lights up, and I get warm air regardless if I have recirculation on or off. The blower motor obviously works fine and I can hear it spinning away, but I don't see the RPM's change at all when I toggle the A/C button nor do I hear a click that for some reason I recall hearing before, of course it could just be thinking there is a click like my other car. Anyways, any idea's what it could be? I did some searching online, found someone say condenser, another a relay which I am not sure where that is at, and another say pressure in the lines.
I hooked up my laptop and ran INPA and found no stored faults, all modules online and reporting fine. So I am thinking it is something mechanical since no faults exist. About a month ago I changed out the Diesel Exhaust Cover p/n: 11 71 7 812 513 because it had a faulty weld in it and was putting black particulate all over the engine bay which seems to be a common issue with the E70 Diesel. Vehicle is out of warranty so taking it to my dealer is not an option for me.

Any ideas on how to test it to figure out what it might be?