As this picture present what i'm doing is creating a new layer of the same layer that makes the light effect to the car's lamp. The reason i'm doing it so because to make the light more darken so that i will kind a look real. I create this new layer by right-click on the layer that is the one that makes the yellow light, then i select duplicate layer. Then it will appear another new layer but as the same as the original layer. By doing so, it will make the lighting effect looks more darken and real.