Like Billy said, the blower moves air and has nothing to do with hot or cold.

Sounds like a slow A/C leak. The a/c compressor won't run when the R34 pressure gets low, that would explain the sudden change in temp. After a recharge, the compressor will start working like normal again until the pressure drops out (again). That would be my guess, you can get a recharge with red dyed R34 which will help you locate any leaks.