Chosen Solution
Replaced HDD with SSD and now fan is going crazy, I did attach the temp sensor to it to that bought from here on iFixit. Haven’t put the lcd back on all the way because of this. Can someone help?
Your systems SMC is looking for the thermal sensors within the display assembly which is why your system fan is running hard and your CPU is down clocked as well to protect it from overheating. So carefully plug in your display cables that should resolve things. If not run the onboard diagnostics. Restart your system and press the D key to enter. Reference: Mac startup key combinations Let us know what you get for an error.
