Yeah, that's a different story isn't it? LOL. My bad for not paying attention to the title.
Have you contacted Clevo, to ask them? They are a pretty customer oriented company considering the price of their products, and in my experience are pretty helpful with questions and concerns. IF there is such a part available, I'd think they'd know better than anybody. If they don't know, then what you've seen is almost certainly something that was home brewed/custom mod by whoever had it. That extra fan header is likely for models that come with discreet graphics adapters. I'd make sure that the diode it is monitoring is in fact tied to either CPU or motherboard thermals rather than being there for use with a gaming adapter because if it is, it may require a specific BIOS image to be functional OR may not function as expected without a graphics card installed.