CPU always at 100% after fan connector replacement

Hello,

Mac mini "Core i5" 2.5 (Late 2012)

I wanted to upgrade my mac mini hd, but at my first attempt to remove the fan connector I broke it off the motherboard

So I took it to a Mac repair center and they reconnected the connector to the motherboard and the fan was working again. The only problem is that it was working at full speed all the time.

The guy at the repair center told me that it happens sometimes but that I can just download a software to regulate the fan, so I didn't make a big deal out of it.

But when I got home, I realized that the fan was spinning all the time because the CPU was always busy at 100%! Even when booting up or even in recovery mode, the CPU is always busy and the fan is running like crazy.

I ran activity monitor and I can see a few process open but they're taking 100% of the CPU. I even tried to reinstall the OS (el capitan) from scratch but with no luck.

Does anyone know what I could do to try and fix this issue?

Can the replacement of the fan connector have cause this?

Thanks!

Sam