Batteries are in fact charged, we did and checked it even twice. :/
We saw, that only one is working, when we removed the blade.
[forgot to post in rules, did it now]
We also thought it might me an wiring issue, but tried to ask here first.
Thank you, we will see, what we can do.
This sounds like a minor wiring glitch and should be covered under warranty. I had a similar issue with my RGBW Emerald saber. The W LED had a fault in the wire and would not illuminate. I sent it back in and they fixed it, no charge beyond shipping, which is less without blade.