You can control the LED lighting effect in the Parameters tab of the client application. Look for the "
ring" section and find the variable "
effect" and the constant "
neffect" there. You can change the lighting effects by changing the "effect" value to any number from 0 to the value of "neffect" (inclusive). The constant neffect is the
number of
effects available. This might be 8 but could change in custom or future versions of the Crazyflie firmware. I think the firmware sets the effect value to 7 by default (all LEDs glowing steady "white" color).
In the "ring" section you can also enable/disable the headlights with either a 1 or 0 (respectively) in the headlightEnable parameter, and fiddle with the glow step and RGB values as well.
If you're sure the LED expansion board (Flykit) is installed in the correct orientation, and it still isn't lit, check the effect value in the Parameters tab of the client application. Try changing the number to see if that affects anything. If you don't have a "ring" section in the Parameters tab, the firmware you're running (strangely) doesn't support the LED ring. Download
an official release that does and update your Crazyflie. If none of this helps, you likely have another issue, maybe hardware related.