Another 300E Air conditioner Benzmac?

[JAlex]

Hi everybody, I talked to Phil when ordering more parts from partshop and he reccomended I e mail Donnie. I'm sure others are having similar problems so here it goes.
First my A/C has been working intermittently for a couple years.......i've lived with it.
Now its not working at all.
I had my A/C buddy put in some freon which he did, so I know my system is full.
My compressor is running and the engine is underload with switch turned on.
Still no cold
Then a week ago the A/C mysteriously starts working........I say cool (get the pun?).
Unfortunatly its not working once again....same thing compressor is full of freon, clutch engaging, underload but no cold.
What can the problem be?
Phil said possibly the drier, could that be it?
the system has not been opened to the outside enviorment although it does have 134 in it.
It dosent seem to be taking heat off the heating side of the system (is that possible) so it appear that it might be something electrictial in nature.
Benzmac and all involved thanks in advance for the assistance
Alex