So, what is actually "needed" out of the donor harness to make the Magnum run? I would imagine it's a little different between obd 1 and obd 2? Following along, thanks for the info!!
To be honest, I don't know the minimal for an OBD I harness since I had an entire Dakota harness that I put in my car.
I would think it would be similar to the OBD II harness like TT5.9mag said, just battery voltage, switched ignition voltage, start signal, and a ground.
You can download FSM manuals for free and trace the schematics to see what the bare minimum is to make it work. I used the 1995 Dakota manual to eliminate what I didn't need from it's harness.