Having trouble resetting the color of an object after the trigger leaves

I have a function written to cause my gameobjects to pulse in color when the enter certain triggers. However, I can't get them to return to the original color after they leave the trigger.

 private void OnTriggerExit(Collider col)
 {
     if (isServer)
     {
         switch (col.name)
         {
             case "pulseTrigger(Clone)":
                 returnColor(col);
                 break;
         }
     }
 }

 public void returnColor(GameObject c)
 {

     if (pulseDict[c.gameObject] == true)
     {
         float r = 0f;
         float g = 0f;
         float b = 0f;

         foreach (KeyValuePair<GameObject, bool> x in pulseDict)
         {
             if (x.Value == false)
             {
                 r = x.Key.GetComponent<SpriteRenderer>().color.r;
                 g = x.Key.GetComponent<SpriteRenderer>().color.g;
                 b = x.Key.GetComponent<SpriteRenderer>().color.b;

                 break;
             }
         }

         c.gameObject.GetComponent<SpriteRenderer>().color = new Color(r, g, b, .75f);
         pulseDict[c.gameObject] = false;
     }
 }

I use these function along with a dictionary that keeps track of which objects have already changed color. I know that the rgb values are correct and the dictionary is updating correctly so I cannot figure out why the color will not update. If anyone could help it would be greatly appreciated.