My AC on the stang has got into the bad habit of cycling on and off at will. For instance, when I took it out for a drive yesterday, the AC did not work for the first 20 minutes, then blew cold for 20, then seemed to cycle back and forth at will. Freon is charged to the proper levels, checked and double checked. When the AC does blow ,it blows nice and cold. From what I can research on here, seems like a pressure switch may be the culprit. Can anyone expound on that, also, I have searched autozone, advance auto parts, and napa online and cant seem to find such part. Any help appreciated. 
