Skip to main content

Model A1311 / Mid 2011 / 2.5 & 2.7 GHz Core i5 or 2.8 GHz Core i7 Processor

429 Questions View all

HDD Temperature sensor gone in 2011 iMac?

It looks like the temperature sensor in the iMac for the hard drive if now gone in the teardown - can iFixit confirm?

If it has gone, this is great, as now I can add and remove a hard drive without Apple's specifications for a temperature sensor built in, like in 2009 and 2010 iMacs.

Answered! View the answer I have this problem too

Is this a good question?

Score 6
2 Comments

After replacing the original 1TB drive in my iMac, (mid 2011), with a 4TB drive, I started using a software solution, TG Pro to monitor and control temperatures. Works like a charm!

by

Thanks TG Pro works like a gem. Great solution and nice insight on all temperatures

by

Add a comment

14 Answers

Chosen Solution

I switched out the hard drive on a 27" 2011 today and I can confirm that the hard drive sensor that attached to the drive is gone. I put in a Seagate 1 TB SSHD and it's running just fine. No modifications were needed.

Was this answer helpful?

Score 3

9 Comments:

Hi, just wanted to check if your iMac is still running ok with out any modifications? Thanks.

by

Yes it is running fine.

by

It appears some have it and others do not and I have no explanation. Maybe @danj knows more about it. I have seen it both ways.

by

@mayer - The first ones had the needed firmware. But, I guess Apple got PO'd and had Seagate pull the magic fix. Now you need the OWC in-line sensor. Besides, if you use any other HDD or SSD you'll need it.

by

@mayer and @danj Im planning to use startech dual bay 2.5-3.5 hdd adapter and put two ssd in it. If I don't need the OWC heat sensor that would be great but if I do where to I put it? Can I just attached it to the grill of the adapter? What is the correct way to do it just incase my imac does not develope to fan issue do I still add the sensor? My iMac is 27" 2.7GHz i5 mid 2011. Thanks

by

Show 4 more comments

Add a comment
Most Helpful Answer

I'm copying a post comment in Appleinsider:

The OWC report is quite inaccurate and I wish they did some more testing or at least read the forums before creating mass panic.

The SATA data connectors are very standard and so is the SATA power cable feeding the hard drive. The only difference is that they used 7 wires instead of 5, probably some extra grounds.

I installed a Vertex3 SSD and used a plain 4 wire Y-splitter sata power cable which effectively discards the 3.3V from the apple's wiring and only feeds 5V and 12V to the original drive. Guess what, fan speed is as quiet as it can get and the Apple Hardware Test passes successfully.

I went further and moved the internal HDD from SATA0 to SATA1 port to better accommodate the SATA connector for the SSD and this didn't create any adverse effects.

Another member of the forum swapped the 1TB WD Black with a 2TB WD Black and again, no adverse effect, Hardware Test completed successfully.

With the SSD in place now, the only thing I can hear is my breath reflected by the glass screen

Report

Was this answer helpful?

Score 8

5 Comments:

The KISS principle in play and offers an excellent solution. It worked for me Poon. Thank you. Now, if I can only figure out where to hide that darn splitter cable safely. It looks so out of place inside the iMac. :)

by

It may be a little late but thanks for this tip! I just installed a WD 5TB Black and Samsung 850 250 GB SSD in my mid 2011 27" iMac and I didn't have to buy adapters or funny cables! I used the SATA Power splitter suggestion on the spinner power cable and a normal SATA cable from the MoBo connector to the SSD and mounted it all under the Optical drive. For the price of $10 for 2 cables my iMac is now a killer and has SILENT FANS !! You are a genius.

by

The correct way of dealing with this is to use this: OWC In-line Digital Thermal Sensor for iMac 2011 Hard Drive Upgrade. This has proven to be the best way to handle the sensor issue which ever drive you put in.

by

4 wire Y-splitter sata power cable worked for me without the extra dollars

by

Add a comment

Y splitter cable works if you are upgrading to SSD. I don’t know why Dan keeps recommending OWC cable. maybe kickbacks from OWC. it’s overpriced and meant to take advantage of naive user.

more info about this sc*m can be found here

https://www.youtube.com/watch?v=pMsk1o1W...

Was this answer helpful?

Score 5

1 Comment:

Working for me!

I couldn't figure out how to route the cables, but then I loosened the GPU screws (T8 and one T10) and pushed the original SATA cable underneath, which did it nicely

by

Add a comment

Thanks Hanno for this hint!

It should be noted here that on the SATA side of the cable the wires 1 and 4 have to be shorted (and NOT wire 2 and 7). This is much easier then Apple's official solution where you have to take the iMac almost completely apart.

For better understanding I have added below some (low resolution) photos. (Sorry for the bad quality).

CAUTION!!! This modification is ONLY VALID when you switch to a solid-state drive (SSD).

DO NOT use this mod to connect a normal harddisk drive! This will most likely result in massive overheat of your iMac.

Block Image

Block Image

Block Image

Block Image

Block Image

Was this answer helpful?

Score 3

7 Comments:

Gee, won't it be just quicker and safer to use this: OWC In-line Digital Thermal Sensor for iMac 2011 Hard Drive Upgrade. This works for any third party HD or SSD. Basically it replaces the internal sensor with an external one so SMC services work correctly in controlling the fans so your system doesn't over heat.

by

Well, also Apple has used this solution on their "SSD only" 2011 iMacs! So it is fully "Apple approved". ;) The only difference is that Apple is shorting wires 2 & 7 on the PCB side of the SATA cable. This mod here works as it should; the fans are no longer running at maximal speed. But yes, if you have the time and the chance then it is better to order the OWC adapter. That will be then a perfect and "clean" solution.

by

Well ... I wouldn't agree Apple supports your direction. Yes, electrically it will work but you are taking the long route. I would use the jumper block Apple offers as a spare if I was doing a SSD only setup. The OWC sensor is still the better solution as you don't need to pop the logic board forward to put in on.

by

based on article at Apple restricts hard drive replacements on new iMacs it's now using a 7 pin hard drive cable and apple firmware inside the hard drive. his is bad because you can't swap the hard drive with common hard drive available in the market.

by

Bodging together an old 2011 iMac years later and I can confirm this fix works.

by

Show 2 more comments

Add a comment

The correct way of dealing with this is to use this: OWC In-line Digital Thermal Sensor for iMac 2011 Hard Drive Upgrade. This has proven to be the best way to handle the sensor issue which ever drive you put in.

Was this answer helpful?

Score 2

3 Comments:

$40 is expensive for the OWC Cable. Hope price drops.

by

@danj does it seems strange to you that only OWC comes up with alternatives to some of the stops Apple puts in their machines? Where are the competitors solutions. That cable should cost $15 or less.

by

No different than DeBeers diamonds ;-} They have a monopoly too.

If the Russians ever released all of their diamonds Russia Reveals Hidden Trillion-Carat Diamond Stash these are industrial diamonds. They also have ton of gem quality diamonds as well! DeBeers Cartel Deathwatch: Russia Set To Flood Diamond Market

I do agree the cost is a bit high given what it is. The same part is used for the other configurations as well (2009 & newer 2012 systems)

by

Add a comment

I’ve been reading this thread and the Y Spitter solution. I am 100% sure this is just grounding the temperature sense data pin 11 on the sata power plug to the hard drive. These sata power splitters and the connections on a standard ATX power supply tend to be be wired with 5 x 3 sets of pins bridged together. 3.3v , gnd, 5v, gnd, 12v.

The 3 pins 10, 11, 12 in one of these splitters are all grounded. Maybe grounding this temp sense pin 11 shuts the fan up. I wonder what apple do in the late 2012+ models when it is a blade only SSD only model with no standard drive.

My other reading implies that in the pre 2012 models there was a blanking jumper plug that was sometimes put in the unsued sata power port to keep the SMC happy with no drive present.

Standard sata power wiring.

Block Image

Sorry if this has been answered I just thought my thoughts may be useful to anyone stumbling across this tread like i did.

Was this answer helpful?

Score 1

4 Comments:

Interesting idea. Is there anyone on this thread that's more technically savvy than I, that might be able to do something with this info to help us with run-away fan speeds?

I continue to be frustrated by the numerous comments above, stating that the "correct" way to deal with the situation is to install the OWC temp sensor, but one can't do that if there's no place to plug in the sensor! I would love to have someone address that point...

by

You don't have a 2011 model, you have a 2012 which uses a 2.5" drive whereas the 2011 uses a 3.5" drive. Which is why the OWC inline sensor won't work for you.

by

@macdoktor - Where did I say one or other?

by

Sorry, my bad. You said 2.5" drive, and my foggy brain read that as SSD. Apologies!

by

Add a comment

I suspect you are right, the splitter Y cable is the easy choice. If you are handy with cables you can also just isolate the grounds and accomplish the same thing but the splitter cable is the easiest.

Was this answer helpful?

Score 1
Add a comment

I just installed a 480GB SanDisk "SSD Plus" in a mid-2011 iMac (with no external thermal sensor on the old drive). I've booted from an El Capitan installer flash drive, formatted the SSD, and am installing El Cap as I write this. No fan noise at all so far. I'm hesitant to clip wires on the power cable, so I'm really hoping my luck holds!

If the fans start roaring when booted from the new SSD/El Cap, then I guess I'll have to try P J Sch's technique...

The weird thing is that I feel like I've swapped drives in other 2011 iMacs (possibly early-2011?) that still used the sensor cable, and therefore require the OWC part that Dan keeps recommending above. I have, and was prepared to use, that part, but there's no place to plug it in on this model!

Learn something new everyday, eh? I hope so at least!

Was this answer helpful?

Score 0

5 Comments:

Btw, how its going ?

I'm going to upgrade my 21.5" Mid-2011 iMac HD to Samsung 850 EVO SSD.

If you willing to share, your experience would help people like me alot.

Start have a doubt to upgrade as Dan keep recomending OWC solution to this works..

by

The machine I upgraded worked fine, without any fan noise. I think your "mileage may vary", but if you open yours up, pull the stock drive, and there is no little cable wired to the jumpers on the drive, you should be okay without the OWC part.

Try it, and post back with the results!

by

You don't have a 2011 model, you have a 2012 which uses a 2.5" drive whereas the 2011 uses a 3.5" drive.

by

Hi JiClark,

Just comeback after 3 year, yeah you right it all work fine without using OWC part. Its been 3 years and it all fine. I would recommend anybody to upgrade their iMac to SSD.. its worth every penny.

by

Thanks @googly! I couldn't agree more.

by

Add a comment

I changed out the stock Barracuda 1GB drive after failure using a new 4TB Seagate drive with a 256MB cache. The fan was maxed out once I replaced the drive. I use a software solution, namely TG Pro, that allows the User to control the fan speed. The app also monitors numerous temperatures. Works like a charm.

Was this answer helpful?

Score 0

1 Comment:

Dude! I just used the Trial Version and it worked like charm as you said it! I will most likely purchased after the 14 days trial. Immediately solves my issue. I just put in a Firecuda 1TB because the stock HDD died. The Fan behind the HDD went berserk! Now everything is as peaceful as the frozen lake. Many thanks to you! my iMac is Mid 2011 27" EMC 2429. Have a good one guys!

by

Add a comment

Has anyone had screen blackouts once they’ve installed a new SSD in to an iMac mid 2011?

the computer continues to work but the screen blacks out quite often, it works again once it has been re-seated, but not for long..

‘the screen does not show anything when shining a torch on it

Was this answer helpful?

Score 0

2 Comments:

Hello from Norway! I have bought a mid 2011 27" iMac where it have been innstalled a 1TB SSD together with a 3TB HDD. It is also a Mac FanControll installed. But it is the same problem with black screen on this machine. Some times I have ti restart and some times the screen have to be black before i Can log in. I am looking for a solution om this problem?

by

Did you set the Startup disk pref setting?

by

Add a comment

Is there anything new on this topic?

I have read, that the fan issue with Third-party-drives (esp. SSD) in 2011 iMacs has gone with a SMC-update on High Sierra. So there should be no OWC thermal cable or short out required, because fan speed is controlled by S.M.A.R.T.

Can anybody confirm this?

Thanks for your help!

Was this answer helpful?

Score 0

1 Comment:

The issue is more complex!

A 2011 and older models use a 3.5" drive which requires the sensor. The 2012 & 13 27" also uses a 3.5" drive and requires the inline sensor as the drives heat needs to be dealt with. A 2012 and newer 21.5" models use a 2.5" drive. these are laptop drives which run cooler as they are slower RPM drives. Apple proposed to the standards group an update too SMART. It took awhile but the most of the current 2.5" drives incorporate the update so there is no issues.

While using a Y connector cable can resolve the need for the OWC in-line sensor adapter it should only be used when the 3.5" drive is replaced with a 2.5" SSD and nothing larger than 1 TB. 2 and larger SSD's tend to get a a bit warmer! I strongly recommend putting in the OWC in-line sensor so the system is able to aggressively cool the system when the SSD gets too warm.

2013 and newer 27" iMac's with newer firmware appear to not to need the inline sensor. I suspect this is related to the SMART update Apple was able to get in the standard. So then its a matter of the age of the drive does it offer the update or not if not you'll need the in-line sensor.

by

Add a comment

I’m planning on changing out HDD for SSD on Mid 2011 model. Just wondering if a short SATA power extension cable will ground out the temp sensor wires like Y splitter cable as I’m curious how they could be electrically different.

Was this answer helpful?

Score 0

1 Comment:

A Y cable is still a bit of a gamble. The reason it works is the grounds are all tied together so the line Apple is using is grounded (but not all Y cables do this). Which is why the sensor is ignored. Thats what Apple did just using a jumper block across the logic board header when they offered a SSD based 2011 model. A SATA cable extension most likely won't short the lines or even have all of the lines wired.

This then gets into what is the drive a HDD or a SSD as the heat each produces is higher with high performance HDD's (7200 Vs 5200 RPM). So defeating the sensor can be done it can put your system at risk! Its better to allow the system to measure the thermal load of the drive, hence supplying a thermal sensor is the smarter way to go with a replacement HDD or a large 2 TB or bigger SSD!

by

Add a comment

I think I sorted it out. I soldered 100Ω resistor into pin 11.

Block Image

Block Image

Block Image

Block Image

HDD fan spins at 2500rpm, machine works like a charm and no need to install any software

Was this answer helpful?

Score 0

5 Comments:

I really don't recommend doing this! In your case you are using 2 HDD's which run hotter than SSD's. I would strongly recommend you fix your cable (or replace it) and get the OWC inline sensor so you are assured the system is able to properly meter the thermals of your 3.5" drive.

by

why add the resistor instead of just cutting the wire?

by

cutting wire gives you "unreadable" again. Some resistance gives "some" reading to SMC. I used 100Ω because it's as low as nothing and as high as infinity depends on impedance, conductance, frequency, etc. Truth is I had this resistor and said "whatever", why not 100Ω? and voila, it worked. So I shared my discovery. You all can use the proper solution recommended by Dan, but we are still talking about old macs. Point is not immortal HDD, but a frequent backup. HDD fan in 2011 iMacs gives nothing anyway, no matter if it's 21.5 or 27" Look at the size! Only one fan which has intake from outside. The smallest one, the one which taking air from behind the desk. The worst dust that everyone ignores. Have a look at the foot of your macs. Surprised? Your macs breathing with it. There are no filters in macs vent holes. Lots of this dust stays inside and temperature sensors are powerless against this.

by

@danj Not 2 HDD's. Drives are in Fusion Drive. TEAM one which has 33ºC is SSD, Toshiba (21ºC) is HDD. Where is your hotter HDD?

by

@pete - I have no idea were you are going here, you implied you had HDD's. Even with a Fusion Drive config the issue is not the temp of the drives alone it's the systems ability to properly manage the thermals of the System.

by

Add a comment

So Dan, just to make sure, here is my situation. I have a 2011 21.5 inch iMac. It had a 3.5inch 500GB hard drive, which died. I plan on fixing the machine, but I am somewhat on a budget. If I get a normal hard drive or hybrid drive (SSHD) then I should get the OWC cable with it, because Hard drives generate a decent amount of heat. However, if I replace the broken Hard Drive with an SSD and used a 2.5-3.5inch adaptor, then I wouldn’t necessarily need the OWC thermal sensor because SSDs (especially just a 500GB one that I am replacing) don’t run as hot as normal HDDs. So because of that, I can get away with using a short block or using the Y adaptor, because that is what even Apple used (right?)

Thanks!

Was this answer helpful?

Score 0

5 Comments:

See my notes about this subject. All are from experience and pictures included

by

It makes no difference the system requires a thermal sensor to work correctly.

So taking out your original HDD takes the sensor away. Replacing the drive with either a HDD, SSHD or SSD all require the OWC sensor for the system to work properly .

by

@Pete - The simple answer is the better answer! Cutting wires patching lines is not something many people get into here.

by

@danj Ok, yes, I know the system needs a thermal sensor to work correctly. But because SSDs generate less heat than the much larger HDDs with moving parts, could I get away without using the thermal cable?

by

It's not a question of which runs hotter. It's what the system requires for a data input.

by

Add a comment

Add your answer

PoPo will be eternally grateful.
View Statistics:

Past 24 Hours: 6

Past 7 Days: 47

Past 30 Days: 148

All Time: 63,894