Hey all - I made an account just to respond to this because I had the same issue. RGB just stopped working and went dark on my ram after installing Armoury Crate. It had worked fine for at least a year prior, and in all other systems.
I see there are lots of other posts online but no one had an answer anywhere for this. I was ultimately able to solve the issue by entering the Asus bios, turning all LEDs to "off" (not sure if this was necessary because I bundled steps) and then I started the bios flash utility. I was going to flash the bios to see if that helped, but I didn't even have to - when I started the flash utility the RAM lit up (though all the other LEDs turned off because I'd turned them off).
Then I rebooted, enabled the LEDs, and after that it worked fine and was recognized by Armoury, etc.
I believe this is a bios issue, some firmware being overwritten or something. RGB is a wild-west of proprietary technology and a total mess. Hopefully they adopt some industry standards at some point, but for now, I hope this helps.