Brief Description: Found the Cause of the AHRSs Failures
Found the Cause of the AHRSs Failures. The clue was that the messages on the EFISs were the same whether power was being provided to the AHRSs as well as when there was no power to the AHRSs on the first attempted power up. I checked the continuity of the power wires between the splice I made with the EFIS power wire at the Avionics Power Terminal and the AHRS's connectors. There was no connection of the #1 EFIS/AHRS Power Terminal and the #1 AHRS. I checked continuity between the #1 EFIS and the #2 AHRS and sure enough, there was continuity. When I was powering the #1 EFIS, I was powering the #2 AHRS. No wonder it all looked right but functioned wrong. I switched the power wires of the AHRSs and fires up the #1 EFIS. VOILA!!! It worked. The AHRSs are now recognized and all is well. Checks of all of the remaining VP Control Unit circuits worked.
Attached the battery to the Vertical Power Control Unit and fired up the system successfully. The system needs to be programmed before it can start controlling the electronics and electricity of the aircraft.