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OWC Thermal Sensor Available for 09-Present iMac HDD Upgrade

iMac_SensorOther World Computing today announced an expansion of the In-Line Digital Thermal Sensor HDD DIY Kits, with support for 2009 and neweriMac models, including the latest iMac Retina 5K display. OWC continues to deliver DIY solutions designed with Mac users in mind.

Key Features:

  • Eliminates excessive fan noise and maintains correct system fan control when upgrading the storage of a 2009 or newer iMac
  • Engineered to work natively with Apple Diagnostics
  • Fixes thermal compatibility issues with third party hard drives
  • Engineered in-house and backed by OWC’s award-winning customer support
  • OWC Install Videos guide you every step of the way

Upgrade Your iMac with Peace of Mind
OWC’s in-line solution includes a custom hardware digital thermal sensor allowing a third-party 3.5” SATA hard drive to be properly installed in an iMac, enabling full compatibility with Apple Diagnostics and the iMac System Management Controller. A convenient plug-and-play cable, the innovative In-line Digital Thermal Sensor eliminates excessive fan noise and maintains proper system fan operation while requiring no software hacks.

Using an OWC Internal HDD DIY Kit, you can easily replace the original iMac hard drive with up to a 6.0TB hard drive (sold separately) for a dramatic upgrade in storage capacity. With easy to follow installation videos guiding you every step of the way, you can perform this upgrade from the comfort of your own home.

“The In-Line Digital Thermal Sensor DIY Kits for iMac embody OWC’s commitment to DIY enthusiasts and upgraders everywhere,” said Larry O’Connor, Founder and CEO, OWC. “Our innovative kit is a complete solution that gives Mac users more options to upgrade their iMac’s internal storage while retaining proper system operation.”


  • OWC In-Line Digital Thermal Sensor Cable and Fan Control assembly for iMac
  • NewerTech 14-piece Toolkit
  • OWC Microfiber Cloth
  • 2 NewerTech Suction Cups
  • Quick Start Guide

OWC’s In-Line Digital Thermal Sensor HDD DIY Kit is available for immediate ordering at special OWC Holiday Saver pricing!

NOTE: All kits are also available as standalone version without NewerTech 14-piece toolkit.

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  • I’ve recently replaced the HDD in my 27″mid 2011 iMac, and am now experiencing the inevitable fan issue. The error code I get in Apple Hardware Test however indicates a problem with the ambient temperature sensor (TA0P) though, rather than the HDD temperature sensor. Can anyone confirm if the OWC sensor will resolve this specific issue, or have I got another problem?

    • Hello Paul,

      Thank you for your question! When upgrading or replacing the main HDD in your 2011 27″ iMac you will need the OWC In-line Digital Thermal Sensor. This will make the fans run properly and your computer will not have any temperature errors!

      Please feel free to contact our Technical Support Team if you have any further questions!

  • I’ve got a mid 2010 iMac with a factory SSD and just bought your 480SSD for the 2nd bay with the adapter. I read that the Digital Thermal Sensor Cable is only for the first bay if a replacement SSD is installed. Is a Digital Thermal Sensor Cable required for the second bay using an SSD?

  • Does this kit work on a late 2009 21.5 inch iMac? I want to upgrade the stock HDD to a SSD and avoid the famous fan noise issues etc.

  • Use OWC’s sensor kit! Non – 2009 iMac drives do not have the correct firmware.

    I have a 2009 21.5″ iMac with the external sensor cable.
    A little testing revealed the following:
    On the original Apple-branded WD Blue drive, Terminal #5 and #6 of the jumper block attach to the cable. Terminal 6 is merely a ground connection to the grey wire. Terminal 5 normally has a 2.5v signal, which gets “pulled down” to ground in a two pulse signal every 4 seconds. This, presumably, contains the temperature data.

    Testing a new generic WD Blue drive reveals the 2.5v signal, but no pulses.

    Testing an Apple-branded WD drive out of a 2007 iMac revealed the same 2.5v with no pulses.

    For the generic drives, jumpering #5 and #6 causes #5 to be shorted to ground, which sets the drive for SATA 150 mode. So, if you put the temp cable on in reversed orientation, you not only disable the fan speed control but set the drive for slower operation.

    I did not perform testing on OWC’s sensor kit, but it appears to work correctly, with Apple Hardware Test passed and fans behaving themselves.

    Many Thanks to OWC for providing a hardware solution to this knotty problem!

  • If I successfully installed a second drive connected via sata using this thermometer–did I void my warranty on my 5K imac?

    • I would recommend checking out two of our prior blog articles concerning Apple warranties and upgrades. They can be found here and here.

      In short, adding OWC upgrades or other 3rd party products does not VOID the warranty.

      A computer manufacturer reserves the right to service their machines with only the original factory parts installed. They can decline warranty work if it is not in its original factory state. This being said, it does not VOID the warranty.

      Our recommendation is to bring the computer back in its factory original state. If you have any questions please feel free to please contact us via phone at 800-869-9152, or 815-338-8685 internationally; by chat; or by e-mail.

  • I have a late 2009 27″ iMac. I’ve already replaced the default Seagate HD twice and have no desire to ever use this brand of hard drive again.

    How can I confirm compatibility with the following drive?

    Hitachi GST Deskstar 7K2000 HDS722020ALA330 (0F10311) 2TB 7200 RPM 32MB Cache SATA 3.0Gb/s 3.5″ Internal Hard Drive Bare Drive

    Can I install this with the OWC thermal sensor?

    Do I have to do anything else to ensure full compatibility, especially considering this drive is faster then the original?

    • On second thought, it looks like that HGST HD model may be discontinued. So what I need is some guidance on which 2TB HGST hard drives I can use, and what special settings (if any) are required during installation.

  • I installed a Mercury SSD using the 2010 iMac upgrade kit for iMacs that had no SSD from the factory. After the upgrade, I have issues with the fans kicking on full speed on and off, sometimes more than others, depending on heavy usage or not. Can I use this adaptor with my SSD SATA connector to fix this issue?

    • The way the iMac monitors the SSD temperature is different than the way it measures the HDD bay temperature. If you have the correct adapter then it shouldn’t be a problem for the fan. I would recommend checking into a fan speed/temperature monitor to make sure it is the SSD that is causing the fan to go high. If that doesn’t work, or you have any questions, please contact our tech support team via phone at 800-869-9152, or 815-338-8685 internationally; by chat; or by e-mail.

  • I purchased the OWC Digital Thermal, SMC Compatible in-line solution for all Apple 2009-2010 iMac 21.5″ along with a 1.0TB Mercury Electra 6G SSD 2.5″ and the NewerTech AdaptaDrive 2.5″ to 3.5″ Drive Converter Bracket.

    In your video you show the Digital Thermal circuit board being attached near the drive spindle. Nowhere can I find documentation or a video on where I should stick the Digital Thermal Circuit board on the SSD. You also don’t mention whether or not the board is a thermal sensor so I don’t have a lot of confidence in just sticking in on the SSD or the NewerTech rail.

    I am kind of surprised that you don’t have some explanation somewhere on your site especially since this is something most noobs would stress about.

    Also what about the 960GB SSD firmware? It appears it’s not possible to update the firmware on this drive so what’s the deal? Is it not possible or not necessary.

    • Hello John,

      The board that you attach to the drive is a thermal sensor. You will want to put that sensor on the SSD in the same place you would with a HDD.

      The Mercury Electra 6G 1TB SSD does not have any firmware updates as it is not necessary at this time. It is possible with future operating systems that a firmware update will be available.

  • i would like to replace the 1GB HD in my 2010- 27″ imac with a samsung 1GB evo850 ssd.
    do i really need the thermal sensor kit you recommend? do the existing connections fit?
    thanks for the help

  • Back in 2011 when I got my iMac I visited this blog often as I wanted to install 2 SSDs in a RAID 0, and still keep my original HDD. I can’t remember what the issue was with why I couldn’t do it at home, I just remember I could only do it if I sent in the iMac. Does this solve that issue? Do you now have instructions on installing 3 drives into the 2011 iMac? I saw the video showing how to install a SSD under the optical drive, can I just put another SSD in the data doubler and replace the optical drive with it? Thanks for the help!

    • The 2011 27″ iMac has 3 internal SATA cables: 1 6Gb/s for the main drive bay, 1 6Gb/s for the SSD drive bay, and 1 3Gb/s for the optical bay. If you want to keep your 3.5″ drive you’ll be using its 6Gb/s SATA cable with it. You may install 2 SSDs inside the iMac though, but 1 will be on a 3Gb/s and the other one will be on a 6Gb/s cable, because of that a RAID 0 between the drives is not advisable.

      Alternatively you could replace your Main bay with a 6G SSD and put a 6G SSD in the SSD bay and create a RAID 0 between them. You could than install up to a 2tb 2.5″ SATA HDD into your optical bay using the OWC Data Doubler

    • The iMac9,1 was before Apple went with a proprietary thermal sensor. That model uses a stick on thermal sensor that can be adhered to a replacement drive with no issues.

  • In addition to making the HDD upgrade possible, is there a SSD upgrade option for those of us with Fusion Drives?
    I’d love to replace the factory 128GB stick with a 512 or larger SSD AND a huge 6TB spinning HD for a massive fusion drive.

    • We currently do not have a SSD replacement for the blade style SSDs found in the Late 2012 iMacs to current. Although you could replace the 3.5″ drive with a 6TB drive using the thermal sensor cable.

      • Thanks for the reply. Looking forward to someday seeing possible upgrades for the flash drives in these iMacs.