I don't know about the earlier cars but the DIC on my 05' will say "Starting disabled due to theft system" or worded very close to that. I haven't swapped in my old PCM because it pulls full lean on me so I've only the experience of replacing 1 PCM but the starter didn't even try to turn over when I switched PCM's until I went through the learn procedure. Hearing the relay click is odd unless there is another relay that kills power to it. Do you have a meter?

Jeff