Problems with triggerEnter()

Hi. I want My game object to enter trigger object and t change his target to the next trigger point.But when he enters the trigger it does nothing.

using UnityEngine; using System.Collections;

public class MOvement : MonoBehaviour { public GameObject target;

 void Start () {
 
 }
 
 void Update ()
 {
     transform.LookAt(target.transform);
     transform.Translate(0f,0f,1f);
 }
 void OnTriggerEnter(Collider col)
 {
     if(col.gameObject.tag == "PathPoint" )
     {
          Debug.Log("gg");
     }
 }

}

object target already has tag "PathPoint",and it's collider is trigger.I don't understand why it doesn't work