AIR CONDITIONING PROBLEM

I have a 2005 BMW X5 3.0. I live in Texas and as you know, it can get : FREAKING HOT : here in summer and that is starting to happen. Over the last couple of weeks I have noticed that the AC has been taking longer and longer to kick in and start putting out cold air, and when it does the air is not as cold as it should be.

I have checked the refrigerant level with 3 different gauges and have verified that there is enough refrigerant in the AC system. I have let some pressure out of the system and regcharged it back to the required pressure, which has helped a little, but not a lot.

I have made sure that the compressor is running and that the car is at operating temperature. The temperature adjuster on the center vents is set to cold and the AC is set on MAX.

Does anyone know what the issue may be or if there are any known issues that may be causing this. I am fairly mechanically literate so I am hoping that this is something that I can fix myself.

Any advice would be much appreciated.

Cheers,

Paul