iMac 20 inch Fans blow at full speed after HDD Upgrade

[pillaishaun]

Hi all. Here's my story

Removed Hitachi HDD from my iMac 20inch(Early 2009) , installed Seagate Barracuda 1TB. I have heard that I should stick to the same brand but its a bit late for that now. The drive works well.

Problem is : Fans run at full speed from the time I turn the computer on and only stops when I shut down my Mac or put it to sleep.

I tried resetting PRAM , resetting SMC , downloaded and tried HDD fan control , ran the smc fan control in Terminal with no luck.

I tried smc fan control and it doesn't allow me to change the ODD speed(Which shows a minimum value of 5100rpm).

My smc fan control values are ODD 5100rpm , HDD 1419 , CPU 3847

I have attached my iStat values here.

I have heard of people removing the temp sensor cable to fix the problem.

My question is , how do I do that? Which sensor cable should I remove?

 

[Sackvillenb]

I'm not sure about removing the temp sensor cable, but I'm pretty sure that all the main temperature sensors make the fans run at full speed if they are not detecting a proper connection... so maybe one of your sensor cables is simply loose or improperly connected?

 

[pillaishaun]

I'm not sure about removing the temp sensor cable, but I'm pretty sure that all the main temperature sensors make the fans run at full speed if they are not detecting a proper connection... so maybe one of your sensor cables is simply loose or improperly connected?

I hope thats the problem. Maybe I should open up the Mac tomorrow and give it a try. Thanks for the advice.