Well, you'll just have to change these numbers in the carcols.xml and carvariations.xml. Carcols, it'll be at the top because it's the first vehicle in the file. Carvariations, will be the first segment too, but you'll have to scroll down until you see this. Try a random 3-5 digit number without repeating, but I would try mimicking the other cars a little bit with it. You most likely have some sort-of confliction going on with another car, or a graphics mod with messes with the carcol ID's. I'm not going to troubleshoot the cars for another light ID when I already have one that works. If multiple people have this issue then I'll find a different number and upload an update, but you're the only one I've seen with this problem.