Using iMac with broken display.

Long story short, I had a very similar incident as described here: My iMacs Display Screen Fell down!

I had used tape in all 4 corners of the display to temporally attach it to the iMac case, but due to the heat in my home office (no AC) the adhesive must have failed.

One morning I woke up and found the top two corners of tape have become removed and my display was just being held on by one of the cable connectors.

Re-attaching the cables / display did not work, as it is completely black.

Attaching an external monitor, it booted into safe-mode (easy to determine as the screen resolution was very low) then upon rebooting, it booted normally, using the external monitor. The problem then becomes that it is now running extremely slow and the ‘kernel_task’ process is using 500% - 1000% of the CPU according to Activity Monitor.

According to the “Best Answer” in the above linked question, apparently this is what’s happening to my iMac:

The fan running would be expected when there is damage in the sensor lines going to the display. The system goes into Safe Mode to make sure the system doesn’t overheat. It also slows the CPU clocking as well to reduce the heat it generates which is why your system is running slow.

Now my question becomes, is there a way to disable this behavior? I have reset the PRAM and SMC, but still no luck. I am looking for a way to tell the OS that the internal monitor is no longer attached such that it will ignore the sensor and run normally. Is that possible?

Justin