I recently replaced the ribbon cable which connects the top case assembly on my macbook pro 4,1 (early 2008). My keyboard is now working but unfortunately the fans are reving up to 6000 rpms and staying there. after a visit to the apple store i've discovered it's due to a faulty palm rest heat sensor.

surprisingly, the genius at apple failed to inform me that this particular heat sensor is actually part of the cable i replaced.

now i could go buy another cable, but seeing as these run $80 a pop i thought wouldn't it be nifty if i could tell my mac to simply ignore the faulty sensor and just rely on the 13 others which are working fine.

presumably this is a function of the SMC, but can it be changed?

as a temporary workaround, i found a nifty little terminal utility which allows me to set a slower fan speed. obviously this is less than ideal for a variety of reasons, but it does prove that user interaction with the SMC isn't impossible.

any ideas?

2 Answers 2


I have the same problem. I used this program. You can set which sensor (only one as far as I can tell) to tip the fan to higher speeds. Best solution I could find, but if one of your other chips overheats, you might be out of luck.



You could install "HDD Fan Control" and control the fan speed with different parameters. It's very good but costs 35$.

  • interesting. does hdd fan control affect all the fans in the laptop? Commented Jun 19, 2013 at 5:59

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