Thanks for the clarification. I measured the resistance between pin 4 of the front panel header and the ground pin of a fan header and the resistance is 0Ω. So that the ground pin of the PLED is not connected to anything, doesn’t seem to be correct, at least on my board.
Since I haven’t had any problems with the power LED of the Chenbro case and other mainboards, I thought it was a problem with the Clearfog board. But they’re right, the Intel spec says 5V. Sorry for that.
Since I didn’t like the blue LEDs on the case anyway, it was a good thing that I now have a reason to change them. 
