Well for sure the A/C request signal is serial data and seems impossible for you to "request" it. Here's what I did. I used the A/C request from my Volvo A/C switch (12volts) to turn on the A/c relay. Forget about the actual E40 pinout. It works perfectly and the ECM (e40) will recognize the A/C through the high side (GM) pressure sensor (as long as you have it installed). The fans will work absolutely flawless as will the elevated idle. Don't ask me why I'm a mechanic not an electrical engineer!
As for your problem you could just hook the violet or yellow/black wire to your A/C relay and have it come on. Here's the schematic below.
Not to hijack your thread Chris but I hope one of the aftermarket companies will soon come out with a "programable" BCM that will work with a GM Ecm. Wouldn't it be neat to have the doorlocks and anti-theft, A/C and battery light... all that stuff work with the E40? I had to buy a tach adapter from Dakota Digital to get my factory tach to read the E40 speed signal. I guess none of the tachs use coil primary for tach input anymore. OUCH ...can you say 40 volt spike to the instrument cluster?
Probably not far down the road one might not be able to swap in a late model engine in an older rig because of all this CAN bulls#it.
I bet that RX7 is a blast to drive. My wonderful wife has a first year Z3 Bimmer with 28,000 miles she doesn't drive anymore (not even to the golf course WTF?). I am threatening to install some real LS power in that! 01 Vette motor sitting on the floor I picked up for $300 bucks. Too many project not enough time.
Good luck Chris you WILL figure it out, we all have to put our heads together
John