I have been having a problem of Hot Air blowing out of the passenger front vents when the A/C is turned on.
One side note to this.. Until you replace or repair the actuator, you can usually turn off and on the motor and it will go back to cold when it does the reset. It also helps to keep the temp set to the lowest setting so the computer doesn't try to reposition the blend door and it stays on full cold.
Mine is currently in need of attention, but being lazy, I just work around it for now. So I'm quite experienced at restarting when needed.
The cause of the problem is the position sensor in the actuator (a variable resistor) is dirty and not making good contact. While I havn't done it myself (yet) I've seen it said that you can open and clean that resistor and it'll work fine again.