It has auto controls I believe. The link below is a picture of it. I don't know if the link will work.
http://http://www.monsterautoparts.c...s/15-72667.jpg
-I bought a controls unit and put it in thinking that might be it and it was not.
-When I got it recharged and filled at Jiffy Lube they found this problem and told me the compressor turns on and off and vaccum was good. They couldn't find why it was doing it. The receiver dryer and low side line I do not know about, I will have to have someone look at it and tell me. I do not know much about vehicles engines.
Thank You so far.