Two months of frustration over nothing more than a loose fuse.
Not much to write up about that.
Just that the fuse panel socket connections are very prone to loosening.
After I rewired the Water injection pump power supply with its own fuse, the horn did not work because I had temporarily tied into the horn fuse and that had created another loose fuse connection. I fixed it quickly with my new knowledge by simply bending the tabs for tight contact.
I think if someone who didn't know what they were doing electrically, tied into one of the fuse circuits, it could create an overloaded relay to fuse and melt that could cause a fire.
I'm still keeping a close eye on this panel.