fans on 2010 iMac run continuously

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fans on 2010 iMac run continuously

Howdy,

I'm well aware this is an obsolete machine at 10+ years old. That said, it still works with the exception of two annoying problems, one of which I fixed today. The first problem was a failed internal hard drive I had just left after switching to booting from an external drive. Because it was still connected, it would generate random error messages but it was the clicking noises upon waking that were annoying. I fixed this today by by removing the internal hard drive. The second problem was that the fans run continuously. I read that this is posssibly related to the hard drive temperature sensor and that some had solved this problem by installing a Sata 15 pin to 4 pin female adaptor to the hard drive power cable-not hooked up to anything. Didn't ask why, just tried it. However this did not fix the fans running. I don't know why, but I'm not crazy about the second solution posted here to download a program called hd fan control from crystal media. 1. because it's not in the App Store and 2. because I'm wondering if the fans are a result of something else, like the lcd temperature sensor and thus shouldn't be messed with. Any thoughts appreciated on another approach to solving the continuously running fans-terminal commands?

Jeff

iMac 27″, macOS 10.13

Posted on Jan 30, 2021 4:10 PM

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Answer 1

den.thed

Level 10

82,444 points

Jan 30, 2021 4:46 PM in response to el beagle amable

Everyone of the temp sensors (including the one inside of the internal drive) are tied into the iMac's System Management Controller. If any sensor is missing or broken, then the SMC can not properly control the fans.

What you will need now, is an inline thermal sensor to replace the drives internal sensor.

see > https://eshop.macsales.com/item/OWC/DIDIMACHDD09/?gclid=EAIaIQobChMIlrie1vXE7gIV9yCtBh3vJw3QEAAYASAAEgKuz_D_BwE&gclsrc=aw.ds

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Answer 2

Jan 30, 2021 5:11 PM in response to den.thed

Hi Den,

thanks for the quick reply. I had seen that fix as well but your explanation was helpful in understanding why. Since I've long been using an external drive for booting and storage, I didn't need to replace the internal drive. The part you reference, the inline thermal sensor, list it as being used when installing a new upgraded or replacement third party drive. I'm not replacing the drive with anything and just leaving the space empty however, the Sata to 4 pin adaptor was listed as "effectively the same" as using the in line thermal sensor-have no idea why but that was listed as a fix for a couple of folks on a stack exchange that were not replacing or upgrading drives. Anywho, all to say if I'm not replacing or upgrading the drive would this still work?

Jeff

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Answer 3

den.thed

Level 10

82,444 points

Jan 30, 2021 5:19 PM in response to el beagle amable

Doesn't matter if you are replacing the drive or not.

The problem is that you need to replace the sensor with a compatible sensor and the in-line sensor in that harness, is what you need to fix the problem.

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Answer 4

Jan 30, 2021 6:57 PM in response to el beagle amable

Temperature sensor was built into the hard drive you removed.

When you removed it, you removed the sensor.

I suggest a nice Western Digital Black, with 256K cache.

https://www.newegg.com/black-wd4005fzbx-4tb/p/234-000G-000W6

NewEgg is out of the Blacks right now a 7200 RPM Red would work...

(Make sure the seller is NewEgg)

https://www.newegg.com/red-pro-wd4003ffbx-4tb/p/N82E16822234345

or a Samsung EVO 860 SSD from NewEgg,

https://www.newegg.com/samsung-860-evo-series-500gb/p/N82E16820147674

Get the 2.5 to 3.5 adapter if you get the SSD...

https://eshop.macsales.com/item/NewerTech/ADPTADRV/

Note that the 2010 iMacs came with a SATA II(2) drive, 3 gigabytes a second, but have a SATA III(3), 6 gigabytes a second, controller on the motherboard. An internal 7200 RPM drive with 128K or 256K cache will run very fast, and an SSD will be even faster...

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Answer 5

Jan 31, 2021 8:44 AM in response to mattwithcats

Thanks Matt,

Assuming these new drives have built in thermal sensors? or do I need both the new drive + the above mentioned in-line sensor? This seems to be the case but at this point it's all a bit confusing. From other post I've read, this is what was required but appreciate your clarification or input on the matter.

Jeff

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Answer 6

den.thed

Level 10

82,444 points

Jan 31, 2021 9:45 AM in response to el beagle amable

el beagle amable wrote:

Assuming these new drives have built in thermal sensors?

The original drive had a build-in temp sensor.

do I need both the new drive + the above mentioned in-line sensor?

No. As I mentioned yesterday, you only need to replace the missing sensor.

For more info on this subject, see > https://eshop.macsales.com/blog/19617-diagnosing-2009-2010-imac-fan-speed-issues-after-upgrading-the-main-hard-drive/

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Answer 7

Jan 31, 2021 10:31 AM in response to den.thed

Hi den,

thanks again. Call me dense, but reading the blog, there is no mention of an option for not using a drive- which begs the question of just how you use the inline thermal sensor without something to connect it to. I'm happy to buy it but want to be clear on it's application. I see the OWC in-line sensor first connects to the SATA power. I suppose I could just stick the sensor module to the chasis then plug into the thermal sensor port on the computer. I have a email out to OWC in the meantime.

thanks again,

Jeff

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Answer 8

Feb 6, 2021 11:56 AM in response to den.thed

Hi Den,

To wrap up. This solved the fan issue. Thanks very much for the input.

And for the archive, I purchased the in-line sensor from OWC*(Other World Computing) and they do not officially list using this as a fix for an iMac with no hard drive, nor when asked, will they speculate. I attached the in-line sensor to the SATA power cable, left the data cable unplugged, then peeled off the sticky back and attached the thermal sensor to a plastic divider near where the old hard drive was located. Lastly,I plugged the thermal sensor cable into the HDD sensor port on the computer. Prior to this install, the Hard drive fan would spin up to 5,000 + rpm after a few minutes. now all three fans run at about 1,000 rpms.

*Note on OWC: Other computer parts stores sell this part but it is generally marked up from a little to a lot. OWC produces and sells this item.

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Answer 9

den.thed

Level 10

82,444 points

Jan 31, 2021 10:49 AM in response to el beagle amable

Yes, just stick the in-line sensor onto the empty hard drive bracket.

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fans on 2010 iMac run continuously

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