When I first saw the gap under the screw of the fan cover on the FLSun V400 effector, I thought it was a perfect spot for a led that would show the printer's state, just like the ones on the voron hotends.
I designed a mount/difussor for a individual neopixel led consisting on 2 parts:
Both pieces are printed with 100% infill and at the lowest layer height you can print. Since models have small walls going too high in could result on some details not being printed.
I recommend printing the difussor in white colored filament. Transparent one could work too, but the light could be too intense.
Suitable for this model of Neopixel led:
https://www.adafruit.com/product/1312
The author hasn't provided the model origin yet.