S40 T5 2004.5 A/C MALFUNCTION

[amemoral]

My S40 T5 2004.5 have a problem with the A/C, every other week when I leave the office and my car is pretty hot inside the A/C starts woking normally and after a couple of minutes it stops throwing air, it seem like the fan is working but the ducts were closed deep inside in the dash, every time I take the car to the dealer the problem just won't appear and the computer is not recording anything, they told me it could be a computer problem caused by an XM radio that I connected to the factory radio, is anyone having a similar problem?