As I said a few posts above that wire is 12 volts keyed off the ignition switch. That's what you are missing. PCM/SBEC Gets fed from that circuit it does not supply it. If I had the manual I could be more help. I am going off my memory. For sure it is a blue wire that is off the ignition switch. We always called it the J2 circuit.
The wiring schematic that I have shows it (blue/white) coming from the engine control module.
I checked continuity with a meter and it shows it having continuity from the relay to the ECM.
