You also need to know that the Mercedes S500 uses lights converted from FS25. It relies on static lights and vertex color. The rust shader you used is from the early FS25 versions, and it simply doesn’t support these newer static‑light vertex features.Because of that, the S500 lights won’t behave correctly when the old shader is applied, so it’s not my fault. The outdated rustVehicleshader is the issue.