Here's my video showing how the harness works -
https://www.youtube.com/watch?v=ng5S8WmY6pQ
[yt]ng5S8WmY6pQ[/yt]
please note, the video is older.....has the older style relays, but....the rest is the same.
There was a weird time where some capacitors where pinned wrong, causing issues......then there where adapters that the polarity was wrong......
In the end, the resistors need to be hot on both sides.
As for the other company playing with resistors to get it to work.....thats my assumption too - just needs to see the right resistance, and if its not.......well.....stupid trucks.
I am actively looking for someone in the ATL area with a '15 to head to TRS for some testing. I have a local guy with one as well.....but its damn cold here and I have no "shop" to be playing in.....ya know? But, I'll freeze my nuts off to figure it out if needed!