Hi

This car was unused and left out in the open for 2 years, and I started using it again in December. The AC worked fine in the cold, and warmed nicely. This week, I tried to use it to cool, and it just wouldn't cool. The fan came on, it felt like it would start cooling initially, but then just kept circulating the air.

What should I look for?

 

Does the compressor clutch engage? If so then there may be either not the right amount of r134a. Another thing is maybe there is a block causing abnormally high pressure.

One more thing to check is, does water come out of the drain tube under the car? Maybe the evaporator is icing up.

 

This model is known to develop leaks. Buy a refill can from Walmart. If you get the can that comes with the gauge, you can at least tell if the system is working properly (for about $15). If this gauge tells you that the system is not pressurising, you have located the problem. Locating the leak is your next drama.
Honestly...with the complexity of todays auto HVAC systems, you are better off taking the vehicle to a specialist...or someone with all the tools & gauge sets required.

 

Do not add R-134a to your system unless you are sure that you are low.

That gauge that comes on the can is not that accurate IMO. Hooking up a manifold is the best way to test for pressure in the a/c system.