AC not blowing cold, 2010 Jag XF Supercharged. Once i turn the AC to lowest setting air gets cold, and then i adjust the temp. It will then continue cooling to the desired temp setting. Once the vehicle is parked and engine shut down the issue resurfaces. The cooling system will not engage until i turn the temp setting to the lowest possible. Could this be compressor failure, or just a simple leak or low refrigerant issue? I have also noticed on warmer rainy days an extensive amount of condensation on the inside of the wind shield, the defrost won't clear it as quickly as it did before.

 

I would take it to a shop with an A/C recover/recharge machine. That machine can check the pressures to see what's going on and also remove all the refrigerant, and weigh it to see how much was in the system. Weighing the refrigerant will tell you for sure if it's low which would mean you have a leak. If you have a leak, they will add dye and find and fix the leak. Then they will refill it to the right spec by weight. Don't add refrigerant yourself from those cans at the parts store. Those cans do more harm than good by easily overfilling and potentially adding damaging air into the system, and they usually have stop leak that has never stopped a leak in the history of mankind, but it can clog up your AC system and turn a small leak into a big problem.

The condensation on the windshield could be the seals in the air distribution box flappers going bad and letting more cooled air flow up through the defrost vents. Not something worth fixing.

Here's what the machine should look like. If the shop doesn't have one of these, go to another shop: