Another update from today - the MMDC is installed, but did not notice anything "lighting up", so I started tracing power from the batteries. Didn't take me long to find an issue - the voltage regulator (called LSDC in the specs) - the 24V and 12V lines from the battery to the LSDC are good to go, but the 'load' outputs - 24V measured 24V - the 12V line measured 24V. Appears something is not working correctly. This also means the 24V is going in the PDM where there should be 12V - luckily the K2 relay stopped it. I have a spare LSDC (in the pile of parts) - I'll try to test that one before I swap anything ... I suspect theres a reason they removed it though...
Another finding - I have ABS, so this is an A1 truck - very good news, as I suspect the CAN bus lines/etc are run, and should work. Also gives me hope the new transmission controller will work with the existing - still have to troubleshoot why I can't see anything on the diagnostic port, but suspect the power issue above may be a part of it.
Question for any electrical experts ... anyone know where CB60 is located? The schematics are showing this is the line from the voltage regulator to this 40A circuit breaker - and supplies power to the C7 ECU - but not in the dash 'boxes'. And not seeing the lines from the voltage regulator to the engine, so wondering if I need to add it...
Thanks for reading!