Based on past experience from everyone here, you won't be able to find a wiring diagram on any Keystone equipment (unless someone did a diagram for themself and is willing to send it to you)
Now: "2 stud junction and it is all rusted and needs the be replaced. It appears to have a resister in it and have no idea what this is for"
This is a auto reset circuit breaker. There should be two of them. My guess would be they are 30 Amp breakers. You can find them at Auto Zone or most other parts places.
If you do a search for wiring diagrams on here, you'll find that a "whole bunch of owners" want a diagram, but none of them have found one either. Welcome to "our crowd"