ISX no cruise or eng brake-multiplexing issue

[ITgirl]

We are desperately seeking help regarding a 2013 Kenworth T8 with a Cummins ISX - vin 1XKDD40X2DJ347571 which came in to us for a loss of cruise control and engine brake and with all of the SAE J1939 Multiplexing set to DISABLE and we believe that a previous shop has flashed the ECM multiple times causing the ECM to lose the "enables" and "source addresses." This is our first time to see this truck in our shop.

How do we find out what the source addresses should be?