Looking at the diagram the diodes will allow current go from a bad switch to the coil and for sure will burn it out, smell the coil and see if they stink like East Chicago . I have burnt a few with test light probe touching two terminals together.
That courage had 68 hours on it. The problem had nothing to do with Nylon parts. If I had to blame something it would be dull drill bits,wore out tapes leaving a 50% thread contact on all the hole they drilled, not sure if thread locker would have held them.Workmanship not Nylon. I have been...
I had a Kohler Courage that like many other s the block cracked after most of the bolts came loose on top. I am attaching the parts pictures for you to get the full flavor of plastic.