2012 iMac - Fan Issue - Help me Short the SATA cable

[pbedrosi]

All sorts of articles on 2011 and older DIY hacks to short the temp sensor wires on SATA cable. Nothing for 2012.
1) I don't want to buy the OWC sensor, nothing against them and I have bought this cable in the past but its feeling a bit like snake oil'ish
2) I don't want to run software

I just want to cut the MF cable open, cut the red? the blue?....anyway cut 2 wires like MacGayver, short the wires, and get on with it.

Anyone done this? why am I the only one with 2012 iMac fan issues after 2.5" SSD install? something else wrong with my upgrade?

 

[DeltaMac]

Don't care for OWC?
iFixit also sells a DIY sensor cable for the 2012 iMac

iMac Intel 21.5" and 27" (Late 2012-Early 2019) SSD Temperature Sensor

Add an SSD to your iMac with this cable. A temperature sensor for the SSD is included.

www.ifixit.com

 

[pbedrosi]

Nothing against either iFixit or OWC (customer of both). I think this fix is stupid for 2.5" SSD install.

 

[pbedrosi]

So I tried the hack at SSD pin level from this logi.wiki guide for 2009-2011, not 2012 but I gave it shot on a spare 128GB SSD.

Logi.Wiki

I shorted pins 12 and 11 - small piece of solder material cut and soldered. This hack did not work. I may try pin 11 and 10. To clarify, the SSD works as normal, but it did not address the fan speed issue.

 

[DeltaMac]

Now the waiting is over... OWC has their thermal sensor cable on sale -

OWC In-line Digital Thermal Sensor for 27-inch iMacs

OWC's in-line solution is the only hardware digital thermal sensor on the market allowing a third-party SATA drive to be installed in your iMac.

eshop.macsales.com

 

[pbedrosi]

I still need help.

I thought the issue was the 2.5" SSD and lack of temp sensor. I opened the machine back up and removed the physical drive, the HD brackets, and SATA cable.

I restart the machine and fan still comes on! I only have the WD Blue blade SSD installed backside of the logic board.

All else is working fine, so I don't know what could trigger this. Not I'm in the process of re-installing Catalina. PRAM/VRAM reset next?

 

[pbedrosi]

I only have the WD blade drive on my iMac...why is the fan still running full RPM? SATA cable completely removed..HELP

 

[DeltaMac]

The fan is running, because there is no temp sensor attached. No sensor, the fan defaults to full speed.
That's the "why"... I think there is a way to bypass the sensor, some kind of kludge to short across 2 or maybe 3 contacts on the hard drive SATA connector. Not something that I have taken much time to discover.
There's a software solution. Like you, I don't want to use software, when there is a hardware solution.
So, another method (one that I have used maybe 10 times over the years), when replacing the original hard drive, usually with an SSD, using the custom adapter cable that bypasses the original temp sensor.
I'm sure that others have figured out the "short these contacts" fix. I prefer to do the adapter cable fix - because I know it works.

 

[pbedrosi]

I have nothing to connect the temp cable to, the SATA cable and drive are completely removed

 

[DeltaMac]

Next step would be to reconnect the SATA cable to the logic board, so the adapter cable has somewhere to connect.

Or, there's always the choice to use fan control software.