Good, you finally circled back to my post #26, now that you understand it. I know that takes a while. I should have also explained the temp switch. It screws into a fairly small, threaded hole in the side of the thick round pad on top of the filter/drier. That is just to hold it against the metal, the hole does not penetrate a pressure boundary (as mentioned above). I bought one in the last year, maybe $12 and maybe ebay.

Someone kludge in the big silver relay in place of the temp switch (didn't have one?) and wired it so the relay turns on via the pressure switch (when AC compressor turns on?). Good you posted photos or we never would have been able to help you.