iMac Intel 27" EMC 2309 (Late 2009, Core 2 Duo 3.06 or 3.33 GHz) ID iMac10,1, EMC 2374 (Late 2009, Core i5 2.66 GHz or Core i7 2.8 GHz) ID iMac11,1

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CPU fan reads 0 but all fans going at full


I recently reflowed a faulty graphics card from a late 2009 iMac (successfully) as per JDW's excellent YouTube found elsewhere here.

However in reassembly all the fans are going. Istats showed CPU fan as zero. Did several SMC resets. Checked everything. Not due to missing resistor seen in other similar cases.

However during reassembly this piece was seen in bottom of case. Can anyone idenify it or suggest anything else to try? and

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@khitomer - Hi, Liam can you please give us your exact model so we can help you.

Go to this web site EveryMac - Lookup and plug your systems S/N in it will give you your exact model info. Paste the system URL here for us to see.


Thanks fro your reply Dan. Glad to hear the part is not something important, though I'd hoped that was the issue! Lol. System is a late 2009 iMac. What other information would help? I've run iStats and it shows fan speeds, and the CPU fan reading is zero. I've tried changing the fan speeds using istats and macfans but none of these seem to have any effect on any of the fans?


Well that limits it to 4 different series ;-{ 20", 21.5" 24" & 27" not including the different CPU options.

Can you pick yours out of this list if you can't use the S/N method I gave you above (click on the blue URL links): All 2009 systems.

All we need is the series as they are all the same within the series.


It's a 2.8Ghz Core i& (i7-860) late 2009 27 inch MC507LL/A model A1312 (EMC 2374) ID iMac 11,1


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2 Answers

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What I can tell you is the little metal part you have in your image is one of the alignment pins for the display. Nothing to worry about.

As to your fan issue depending on your model you could have either a mis-connection or a bad fan. We really need to know what you system is to go further.

Update (06/29/2017)

I gather you are still having problems.

Can you give this app a try: TG Pro it does a better job of listing all of the sensors and fans with there running status. Paste a screen capture of the main screen (all of it) so we can see all of the sensors and fans details into a fresh answer and then click update. From what it sounds like you may have damaged one of the GPU thermal sensors or have a mis-wired fan.

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I have the same problem. How did you solve the issue?

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Liam D will be eternally grateful.
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