I love hardware mysteries. I mostly drive old 90s enthusiast cars, and I have had my fair share of undocumented switches. The most surprising to date was in a

I love hardware mysteries. I mostly drive old 90s enthusiast cars, and I have had my fair share of undocumented switches. The most surprising to date was in a Nissan Silvia, from 1989. Sometimes it wouldn't crank off the key, given the solution chosen it must have been a wiring issue. Instead of fixing that wiring, the previous owner had directly wired power to the starter via a "missle switch" style switch, and instead of mounting it anywhere remotely useful, it was just spliced into the loom and sat on top of the rocker cover in the engine bay. So if it wouldn't start, I had to leave the key at "on", hop out of the car, bump that switch and then it would start. Obviously standing in front of a manual car while starting it is the dumbest thing next to wiring your starter to a switch in the engine bay. Fortunately I never ran myself over. Another one, I will keep short, a 97 Skyline would only light up ready to start 1/4 times. Seemingly randomly, on key bump. Turns out the flash memory for the fuel map had corrupted, and depending on the temperature and a bit of randomness from the sensors, it would only hit a corrupted cell occasionally. It got worse and worse as more of the table corrupted, until it would only start say 1/60 key bumps. It was a dodgy power wire causing the corruption, and fixing that plus reflashing the tune fixed the issue.