LOL - if your a/c is 134 it may be doing as good as it can do. The part you are asking about is called the monovalve. Open the hood and look on the firewall to the right of the battery. Should see some hoses and wires going to the monovalve. The problem that I have had with mine was not heating up the car during the winter at certain times. You may can feel the hoses around it and try to ascertain by hose temp if any water is flowing around it anywhere. Understand that even when these a/c are charged and in good working order they still leave alot to be desired. When getting mine going I had to replace the compressor, the push button unit and the dryer. When it is 70 dF outside I can get 42 dF out of the center vents. That is about as good as it will do. I suspect my evap has alot of external buildup.

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Jim