
In the image above, there are two ends of a brown wire near the alternator with some type of factory termination on them. The one can be readily seen at the end of the brown wire, the 2nd is just below it sticking up where you can see the tip of the copper wire at the top of connector, it kinda looks like a valve stem jetting up from the harness. (Maybe that is so you can easily check the air in the tires if the car won't start:) I'm pretty sure the brown wires were a single factory oem splice that broke. That is, it was similar to the two red wires shown connected in the same image.
Its an '82 spider, the wiring diagram shows a brown wire terminates at the Starter + post, so does the splice makes sense? Not sure why they spliced it except for maybe easy troubleshooting?

