for others who look at this post down the road....
It has been my experience (limited as it is) that MTH has changed wiring at different times on models. I would always recommend doing wire tracing even on similar models and their tenders. Even on newer PS3 diesel models I have worked on, the wiring is different on different releases. This is a problem when installing sound sets and the lighting functions are changed. It is obvious for safety that swapping tenders is a big no no.
I have swapped out tenders several times. Each and every time, I have traced the wiring. I have replacement tethers that have thicker yellow and white wires designed for the motor connection. Yet I have had to swap out the wiring to utilize these wires in their properly designed place.
