1997 Air Conditioner will not cool.

I recently replaced my original A/C compressor with an aftermarket one. No problems with installation and added freon until pressure was within normal range on my gauge. However, the air is not cooling. Can you provide some additioal items to consider. I've checked the warm/cool cable to make sure the door was opening and closing and was not stuck.

There's a valve against the back of the engine that the cooling lines are attached. Could that be it? Please provide some typed of checklist for me to follow and thanks

97 Saturn SL-1