John: OK, I'll give that a shot; it still begs the question where the one IR tether wire presently in Lionel's J7 pin1(?) on the motherboard will go once the 3rd Rail harness is swapped in......
And again, NO WHERE in the Cruise "M" instructions does it logically say to use the new harness-they reference using for K-Line locos and that the Lionel harness "will have this same connector attached to the board you remove, and this connection will directly connect to the Cruise "M"."
Sorry I'm being careful as burning one C-note is enough for my budget.....