Any mesh with vehicle_lightsemissive shaders will appear always emissive in-game unless light IDs are assigned. Assigning light IDs allow you to make some faces only appear emissive under certain conditions (i.e. headlights on/off). Sollumz makes assigning light IDs easy.
With a headlight object selected, enter Edit Mode in Face Selection mode and navigate to the Sollumz Tools > Fragment > Vehicle Light IDs panel.
Select the faces of the left headlight that use the emissive shader, then set its light ID to headlight_l.
Notice now that if you unselect those faces, and select the headlight_l light ID, it will select those faces you just assigned.
