Left fan is going nuts

[Whits]

Tech Tool shows everything as being fine. My keyboard and trackpad don't work because of a recent coffee spill, but the fan is also going crazy. It's only one though, and tilting my screen down makes it much noisier.

I plan on replacing my keyboard and the top casing. Will replacing the fan hardware help this, or is there anything else that I can do?

 

[Pax]

Others have posted similar problems which turned out to be failed temperature sensors. I think if the Mac is uncertain about any internal temperature it goes into fail safe and winds the fans right up.

I've not seen only 1 fan go to max though.

Another option might be the fan control feedback connection (wires coming back from the fan to the logic board which report its current speed).

Run Hardware Test, it's on one of your install DVDs. It will show up any failed sensors & I expect it will show any fan sensor problems. I think it only shows a four digit code though, it might take some googling to relate that to a physical sensor.

Note:- iStat shows some but not all temperature sensors, So you can't rely on it, you need Hardware Test.