That worked! Thank you so much!I've been having the same problem. Try this.
Open the Number 68 skin folder that came with the car from URD.
Copy the "ext_config" file.
Open the "2019_D24_ChipGanassi67" skin folder and paste that file into it. Let it overwrite the one there.
Now copy the "Sglow" pic (DDS image) from the Number 68 skin folder.
Paste that into the "2019_D24_ChipGanassi67" skin folder, again, let it overwrite and that's it. Lights should now be green.