I deleted gta v after some issues and I lost the mod that permantely fixed the issue where police cars would spawn "dirty" and the light would be black as a result. with this mod I didn't have to edit anything just place the file and then I wouldn't have black lightbars. Can someone please provide the mod? thanks!

A lightbar being black is a result of a window tint being present on the car. I believe the sheriff suv and police4 (unmarked stanier) has that tint. I'd try to search for a mod that removes the tint.

In case you're trying to get rid of the dirt all together. If I remember well, you need to replace the dirt textures with a fully black texture.

You can clean the vehicles by going into SimpleTrainer and choose Clean Car after you spawned it🤫

Using a trainer or editing the vehicle meta will usually resolve this issue.