I’ve had this issue for weeks now, every other modification in the game works for me. I tried everything, including just copy pasting the sample code from the native docs. There is no error, just the color does not change.
To reproduce:
Go in a car, run this:
local veh = GetVehiclePedIsUsing(PlayerPedId())
ToggleVehicleMod(veh, 22, true)
SetVehicleXenonLightsColour(veh, 2)
GetVehicleXenonLightsColour(veh) -->> this will output 255 which means no color is set