Tried a new model, that didn't work either. Thought maybe it was carvariations.meta, but I never touched that.
UPDATE: Figured out it was carvariations.meta. I had to change the police3 line to police2 for the lights to start working again. Not sure how it was changed because I never touched it, but I'm glad my stuff is working again.
Also, for anyone who comes across this. Just extract the carvariations.meta file to your desktop, edit it with worddoc or notepad, click edit, then click find, type in "police" and hit F3 until you find police3. Edit the line to make it say police2 instead of police3. I'm assuming it's the same as far as other police vehicles go. Not %100 sure though because I only saw Police and Police3. Maybe there are multiple carvariations.meta files?