Did you try to unplug the connector from the Gateway and try to plug it into the other end of the T-Harness, the side not shown in your picture?
Even through the plugs look different from the outside, the the one on the T-Harness being straight and the vehicle's sideways (or L-shaped), from online photos, the actual connectors look to be the same and probably should plug in.
I had time to dig into it tonight. Sadly, the main harness doesn’t have the correct size plug. Anyone else have an idea where the correct gateway is located?
Oh my, right rear quarter panel. Quite a ways from the OBD2 plug. Are we talking about the same gateway? I will take the carpet down on Sunday to look for it. I have a 8 hour drive home tomorrow then a wedding on Saturday.
The gateway location apparently was moved. Check page 17 in the installation manual here:
https://www.fordservicecontent.com/Ford_Content/Catalog/accessory_files/2021_RMST_Common_I_sheet_11_5_20_D1_002.pdf
Definitely not the case on this edge. I have a feeling it might be behind the screen. Are there videos on how to remove the big displays? All I’ve found are the small display removals.