Disable AudioZone

I made a sprite to turn the audio off (button), but the script doesn't work. I have problems with .active thing... Here's the script:

 #pragma strict
 
 var audioIsOn : Sprite;
 var audioIsOff : Sprite;
 var Audio_Source : GameObject;
 
 function Start ()
 {
     Audio_Source = GameObject.Find("homeAudio");
 }
 
 function OnMouseDown()
 {
     if(Audio_Source.activeInHierarchy == true) //also tried .active and .activeSelf
     {
         Audio_Source.SetActive(false);
         // also tried: .active = false
         // activeSelf = false and activeInHierachy = false
         GetComponent(SpriteRenderer).sprite = audioIsOff;
     }
 
     if(Audio_Source.activeInHierarchy == false) //also tried .active and .activeSelf
     {
         Audio_Source.SetActive(true);
         // also tried: .active = true
         // activeSelf = true and activeInHierachy = true
         GetComponent(SpriteRenderer).sprite = audioIsOn;
     }
 }