Attempting first project - Some questions if I may

[Electronic M]

Since you posted while I was writing more info: If you have a spare cord you can try swapping it. You can also do a continuity check on the cord with a DMM. It is possible the cord is fine and the interlock bad, but cord problems are more common. If either cord or interlock is bad you will have to get a replacement for what is bad. There are ways to kludge normal cords on and defeat the interlock, but that is a really crappy way to do it (something to do only as a temporary solution while you hunt the right parts).