Hello,
I just build this new system replacing my old EVGA card that finally died after 12 years.  Strange thing is that the HD activity light is always on solid not blinking.  I verified that I did connect the hd led cable  correctly.  I even flipped it which result in no light at all.  so its connected to the correct location but is just always on solid.  I love to find out out why.  I have 6 hard drives connected to the board and 2 dvd burners so I am using every single sata port on the board.  I know I have types of controllers the Intel and the Marvell.  All the drives work fine no issue the computer runs great.  I think it maybe a bios setting but not sure just from reading other folks online with the same issue on different mother boards had corrected by disabling the second sata controller but I cant do that since I use them both.  I am thinking may be better hd cables that will lock in.  I have read that if the are not seated properly you can get this error as well.  Anyone had this issue ????? love to get some feedback.
 
 

i have checked that and no there is no issue with the led and the hard drive activity cant be a solid light every second of the day for the entire day.  I think is something else.  I did reverse the connection in the motherboard and it shut the light completely no activity.  this was working on my previous motherboard prior to this change in motherboard. thanks for the response.
 

It works backwards, thought the same thing with my corsair case. Always lit, blinks off when active. Funny thing is the m.2 activity light works the right way. Quirks, gotta love em