How to connect iMac temperature sensor on a WD Blue 1 TB?

I have my friends iMac in which he needs a new drive. He got a WD Blue 1TB HD to install. I am trying to help him with it, but the first problem has popped up. Mac uses a temperature sensor on its HD's & I don't know where to plug it into the WD Blue. There is an 8-pin connector next to the SATA , but which of the 4-pin combos do i plug it into?

Any suggestions or help anyone can give me would be greatly appreciated.
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We need to know which model iMac. Alternatively look at the repair guide here for the appropriate model:
Dr. KlahnPrincipal Software EngineerCommented:
The 8-pin connector on hard drives is generally reserved for factory testing, with the possible exception of a 6/3 Mbps slowdown jumper.

I've never seen a hard drive with a temperature sensor; since about 1999 there has no need for such.  All SMART compliant drives return their temperature as one of the functions.

SMART temperature reading
If there is a temperature sensor it definitely does not plug into the drive.
andyalderSaggar maker's framemakerCommented:
I didn't realise iMACs had custom drives with separate temperature sensor connectors either but there you go, proves I don't know iMACs.

I know how to google though, should sort the problem better than shorting the pins out. There's a video on fitting it to the drive as well, the interesting bit starts about 4 minutes in where they start to add the custom sensor to the disk case.

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BlinkrAuthor Commented:
Thanks for the quick response!

Thanks Strung I will be checking out that site.

Dr. Klahn, that is a PC Windows window displaying there, isn't it? My question was about an iMac. Checkout Seagate drives. There is a 4-pin connector next to the SATA connector. That is where the iMac temperature sensor plugs in.

andyalder, this isn't a custom drive situation here. The Seagate drives have the 4-pin connector for the iMac temperature sensor next to the SATA connector. I saw the OWC connector on several of's  videos. I just got one at Amazon.

Now to everyone: I already have a WD Blue drive to use on this upgrade. That's why I'm not buying a Seagate drive. I was checking to see if anyone knew how to connect the temperature sensor to the WD.
andyalderSaggar maker's framemakerCommented:
Sorry, my bad it's a generic drive not customised.

It's the Seagate diagnostic serial port that the apple temperature cable is connected to. WD diagnostic port is not only a different connector it also has a different command language
BlinkrAuthor Commented:
I did use Google & found several videos. The OWC video showed how to install a new drive but it didn't say anything about purchasing the replacement thermostat that you stick on the drive. It just told you to stick it on & connect it. It took a little more research to find that.

But thanks for posting the link. BTW there are 2 videos. There's an old one & then they did an updated video.

Thanks again!
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