2000 Saturn L200 Air conditioning sensor

So. Of course my ac went out this summer. I have had the system drain, refilled and checked for leaks, but for some reason the coolant is not circulating through the system. Because it is not circulating my compressor is not kicking on. Because my compressor is not kicking on, I am not getting cold air. I was told that I need a new air conditioning pressure sensor. I looked in the my haynes manual and it tells me how to replace it and told me to see illustration. The problem is there is no illustration! So now both my father and I are trying to find this sensor. I went to the dealership to see if they had the part but they acted as if they did not know what I was talking about. Of course they want me to come in and have them do everything I have already had done in order to tell me what the problem is. I understand they have a process they must go through, but the thought of paying a $150 for something I have already had done is not sitting to well with me. I am trying to check the small things first before I go that route. I have checked the fuse, tested the lines (as I mentioned earlier) and now I am trying to replace the sensor. Could this be a relay problem or a sensor problem? And where is the darn sensor or at least a picture of it? Any help would be appreciated.