Add Light To Shader

Hi guys I wrote a shader which one blend 2 textures :

  1. _MainTexture is drawed normaly
  2. _SecondTexture is blended to _MainTexture but it is visible when _Mask is on _SecondTexture

Shader work’s perfectly but I dont know how to add light to it.

Properties
   {
          _Color ("Main Color (A=Opacity)", Color) = (1,1,1,1)
         _MainTex ("Base (A=Opacity)", 2D) = ""
         _SecondTexture ("Second Texture (A=Opacity)", 2D) = ""
          _Mask ("Culling Mask", 2D) = "white" {}    
   }
   SubShader
   {
      Pass
      {
         Lighting On
         Blend SrcAlpha OneMinusSrcAlpha

         SetTexture [_Mask] {combine texture * constant ConstantColor[_Color]}

         SetTexture [_SecondTexture] {
         ConstantColor[_Color]
         combine texture * previous
         }

         SetTexture [_MainTex] {
         combine texture  + previous
         }

      }
   }

I trying turn Light On or add tags but when I move any lights to object with this shader then light is not affect on it. I want to achive effect like on standard Diffuse shader

You can use a simple Lambert surface shader, and set your combined textures.
like this Unity - Manual: Surface Shader examples