Here is how i did it, as it was not as simple as just flipping a bit. This is a cut and paste from my notes I kept as I made changes to my PIU:
As built from new ACM(EBay) had issues with Sync, as well as volume as it came out of a Sony equipped Explorer. Found a base unit serial# with Sirius and Sync online, and used that serial# to
retrieve as-built info from Motorcraft site and modified any non-matching entries in Ebay unit
VIN 1FM5K7B89EGB29277
ACM As Built Info:
727-01-01 5A00 2000 00AA
727-01-02 0132
727-02-01 0132
727-03-01 2A5C
727-04-01 0001-0255-53DE
If you unit is close to mine, I can email you my file (Your PIU will have to have Sync)
Tom