I think his problem is he can't control the temp. Like the blend door actuator is stuck on the 'hot side'. Try and take the airconditioning out of the equation just for the moment. Turn it off, and then press 'mode' to select your mode, and then turn the fan on so that it's running without the AC.
Then, when the cars warm have a play with the temp control, go from 32 to 18 and see what happens. Its the middle of winter, so the blend door will just switch from pure outside air, to heating the outside air (leave the re circ button off).
How old is the refrigerent? If it has any at all?