Thanks. Your picture is a big help. I thought the bolt on the inside of the fender was to hold the box down. I've had everything torn down for so long that I forgot and I screwed up taking a picture before I removed it.
I sure hope the loose connection at the terminal could be the cause...
When I was removing my battery box, this short black wire fell into the engine bay. I originally thought it was part of the fusible link that I was going to replace anyway but that's not it.
Is this just a ground that should be connected to the negative terminal and the frame?