This is exactly why I gave you the suggestion to run the A/C, old school style. You do realize, that besides the logic and inputs a PCM uses, all it does, ultimately, is ground the coil side of a relay to turn on the compressor? That is what an LSD (low-side driver) does. On an old school sytem, you can wire a switch on the dash, to do exactly that. Sure it wont be as efficient, but it will be far easier to work with, if you dont plan on using everything.To have the PCM run it requires more than you think. It can be done pretty easily by those who know and understand the operation of all the inputs (and outputs) used; but why ask all this or any of it for that matter, if you have a donor vehicle, from which to pull the entire system from and graft it in? There is no need to reinvent the wheel here,if you want the PCM to run everything, then just install the whole works. You don't have to worry about the anti theft system, if you use a PCM from a truck that was not equipped with one, which also points to my suggestion of NGC (as the easiest to locate). . Your dissertation on using the BUS showed you have at least some understanding of the theory behind it. Most of us that responded, probably understand bus communications well beyond that, which led us here to begin with.
