Reminds me of an old motorhome we inherited from my grandparents. While my father was getting it fixed up, he had to test all the wiring…which was a bit of a chore…the dashboard was filled with custom toggle switches my grandfather had installed over the years for various purposes, not all labeled. The service manual was useless because a fire a long time back had resulted in the makeshift replacement of all the wiring, so many functions had to be determined through trial and error, and a lot of tracing.

One mystery unlabeled switch had no apparent function, and my father spent the better part of the day following the wire from the switch, as it snaked through almost every part of the motorhome, ending at…the other terminal of the switch. It was a dead loop left for future expansion, to be connected to whatever by simply cutting the loop. My grandfather would have been pleased to know his engineering had sent someone on a wild goose chase.