LightSource with Light option selected.

LightSource with Mesh option selected.

One vehicle light source. Can be a Light or emissive Mesh.

• If Light is selected as Type any Unity Light can be assigned. It will be turned on and off according to user input.
• If Mesh is selected as Type any Mesh with Standard shader can be used. It's Emission field will be toggled to imitate a working light. Since this does not emit enough light to be a headlight usually another light source is used in tandem, this one with SpotLight assigned.
  

For an emissive mesh light to work it needs to be a separate object. If the model does not come with lights and blinkers as separate objects these will need to be separated in 3D modelling software such as Blender (free, open source).

When using Mesh light source make sure to tick the Emission checkbox on the material. This lets Unity know that this variant of the material is in use and should be included in the build.

Mesh with Emission turned on.

Mesh with Emission turned off.