unity 5.6.5f1

在看完7.Stealth秘密行动游戏开发-给游戏添加控制器GameController后，我创建了游戏控制器并添加了相应代码后无法控制警戒灯的闪烁，请问是怎么回事？

AlermLight

    public bool alermOn = false;
    public float animationSpeed = 1;//变化速度
    public static AlermLight _instance; 

    private float LowIntensity = 0;//警报灯不亮
    private float HighIntensity = 1;//警报灯最亮

    private float targetIntensity;
    //初始化、赋值
    void Awake()
    {
        GetComponent<Light>().intensity = 0f;
        targetIntensity = HighIntensity;
        //alermOn = true;
        _instance = this;
    }
	// Use this for initialization
	void Start () {
		
	}

	void Update () {

	    if (alermOn)
	    {
	        GetComponent<Light>().intensity = Mathf.Lerp(GetComponent<Light>().intensity, targetIntensity, Time.deltaTime * animationSpeed);
	        if (Mathf.Abs(GetComponent<Light>().intensity - targetIntensity) < 0.05f)
	        {
	            if (targetIntensity == HighIntensity)
	            {
	                targetIntensity = LowIntensity;
	            }
	            else if (targetIntensity == LowIntensity)
	            {
	                targetIntensity = HighIntensity;
	            }
	        }
	    }
	    else
	    {
	        GetComponent<Light>().intensity = Mathf.Lerp(GetComponent<Light>().intensity, 0,     Time.deltaTime * animationSpeed);
	    }

GameController

    public bool alermOn = false;

    void Awake()
    {
        alermOn = false;
    }

    void Update()
    {
        AlermLight._instance.alermOn = this.alermOn;
    }