What is the make and model of your motherboard and what BIOS version are you on? If you're using Corsair's iCUE app, you can set all the RGB's to black on the color wheel.
MSI X470 with the latest BIO's and yes on the iCue as it works very well when the computer is on but when I go to sleep the light on the memory changes and remain on. Don't really need a night light. I can change it to off but I like the light on when I use the computer.