I used a script like this. But for some reason, it's been deleted from my files.doll = '/Effects/_(Effect)/Artefacts/General/Blue.xdb#xpointer(/Effect)'
SetObjectFlashlight ('dolmen' , doll)
Open the data folder - follow the path indicated above, and you can choose a suitable effect there.
Regarding this function: I'm not sure if it will work, but essentially ("grammatically"), it does the right thing.
The manual says that light is set in the map properties, but where is that?