BCM not communicating with ECM?

Vehicle is known to have electrical issues. Layout around engine bay and also bad grounds. If you can, provide me with the wiring diagrams. Also, while I was in midst of replacing my shifter cables, I stopped to double check the replacement cables and weren’t the correct ones even though stated it fits my vehicle but doesn’t have the shims that you pull back to place on the bracket by transmission. Also, the replacement cables have a metal bracket that aligns with the rubber grommet where the vehicle doesn’t have any metal bracket nor would fit that metal piece anywhere. I was using contact cleaner and cleaning around some of the ground areas and on some of the wiring harnesses. I waited over 40 minutes before connecting everything and went to start the vehicle and wouldn’t start and saw the Anti-Theft symbol on the dash. A tech ran an diagnostic and said BCM wasn’t communicating with the ECM but don’t want to get a remanufactured BCM and still won’t start. Got to be a short and or a ground as well. Since prior to the anti-theft. I noticed my vehicle was no crank no start till my cousin had a CAN scan and when we were checking the wiring with the hood up he moved a bundle and that's when we heard a clicking sound. Narrowed it down to a wiring harness that lead to the starter I believe. But I couldn’t find a replacement harness. I carefully removed the wiring harnesses and straightened the wires and placed back in the plug three wires yellow, green, purple.