I recently got a used iMac 21.5 inch Late 2009 Model 10,1for free that had a failing HDD and a bad graphics card. Apple store wanted 600-800$ for the fix. So, I decided to venture on my own being that paying to fix a six year oldiMac was almost the cost of a new one. I took apart the iMac and replaced the HDD with a Samsung 840 SSD that I had laying around and tried to bake the graphics card. The baking has seem to "fix" the graphics card for now and the SSD is working okay. I also ordered a mounting bracket for the SSD and the OWC in-line digital thermal sensor for iMac 2010 that connects to the sata port and provides compatibility for temperature readings. Link:https://eshop.macsal...C/DIDIMACHDD09/ My problem is that the ODD fan is blowing constantly. I've tried re-setting my SMC and restarting my PRAM/NVRAM. I downloaded Macs Fan Control and it shows the ODD fan at 0rpm even though I can clearly hear it on and blowing. I've tried unplugging the fan from the logic board and that does make it stop, but my temperature values all over start to creep up. My HDD and CPU fans seem to be fine and hover around 1100 and 1200 rpms and will respond to my controls in Macs Fan Control. The ODD, does not respond. It just keeps blowing regardless. Here is a screenshot: I know that there is reported issues with the ODD fans blowing on high after upgrading to a SSD, but the in-line temperature sensor is suppose to correct that. I tried to launch Apple Hardware Test by holding down D at start up and the boot process does pause for about a minute but never goes into the test program. Holding down option (alt on my keyboard) D doesn't do anything. So my question is: I installed 10.11.5 from a USB stick made from a download from app store on the new SSD. I don't have the current install cd that came with the iMac in 2009 (Lion? Snow Leopard?) and with the superdrive spitting out every disc I put in, I don't think that is even an option if I did track it down. Is there any other way to launch Apple Hardware Test that I haven't tried? I really don't want to spend 100$ for Techtool pro. Thanks for any suggestions.