how can I change a light with multiple triggers. ?

Hi,

I'm quite new to unity and scripting and i'm having issues with a script. I'm trying to make the color of te light change when I trigger a cube, for now i managed to do it with to different scripts, one attached to the trigger cube :

 using UnityEngine;
 using System.Collections;
 
 public class triggertest : MonoBehaviour {
 
     public float rouge  ;
     public float vert  ;
     public float bleu  ;
 
     void OnTriggerEnter(Collider col ) {
 
 
         rouge = Random.Range (0f, 1f);
         vert = Random.Range (0f, 1f);
         bleu = Random.Range (0f, 1f);
 
         Debug.Log (rouge);
         Debug.Log (vert);
         Debug.Log (bleu);
 
         }
     }

and the other attached to the light :

 using UnityEngine;
 using System.Collections;
 
 public class light : MonoBehaviour {
     
     public Light lt;
     public GameObject trigger;
 
         private    triggertest script;
 
         private float rouge2;
         private float vert2;
         private float bleu2;
 
         
 
     void Start() {
         lt = GetComponent<Light> ();
         lt.color = Color.HSVToRGB(Random.Range(0f,1f),Random.Range(0f,1f),Random.Range(0f,1f));
         script = trigger.GetComponent<triggertest> ();
 
     }
     void Update() {
         //rouge2 = GameObject("cube").triggertest.rouge;
         rouge2 = script.rouge;
         vert2 = script.vert;
         bleu2 = script.bleu;
 
         lt.color = Color.HSVToRGB(rouge2,vert2,bleu2);
 
     }
 }

I tried to make just one script, for the trigger but it doesn't work. Anyone have any ideas why ?

 using UnityEngine;
 using System.Collections;
 
 public class unique : MonoBehaviour {
     public Light lt;
 
     public float rouge;
     public float vert;
     public float bleu;
 
 
     void Start() {
         lt = GetComponent<Light> ();
         lt.color = Color.HSVToRGB(Random.Range(0f,1f),Random.Range(0f,1f),Random.Range(0f,1f));
         
     }
 
     void OnTriggerEnter(Collider col ) {
 
 
         rouge = Random.Range (0f, 1f);
         vert = Random.Range (0f, 1f);
         bleu = Random.Range (0f, 1f);
 
         Debug.Log (rouge);
         Debug.Log (vert);
         Debug.Log (bleu);
 
 
     }
 
     void Update() {
 
         lt.color = Color.Color.HSVToRGB(rouge,vert,bleu);
         
     }
 }

Thank you in advance