Issues with Debug.DrawRay

Newbie here! I'm working on a simple game based around a lighthouse. I want to be able to tell if an object is in the lighthouse's view or not. Figured the best way would be to raycast.

Trouble is, I can't even get Debug.DrawRay to show anything in the scene view. I've googled around the issue, but mostly the fix has been to turn on Gizmos - which I already have!

Does anyone have any insight into why this might not be working? Any great ideas on my overall goal also greatly appreciated.

Thanks!

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class LensBehaviour : MonoBehaviour
6. {
7.     public float lensRotationSpeed;
8.     public float debugRayLength;
9.     private RaycastHit vision;
10.  
11.     void Update()
12.     {
13.         // Simple rotation controls
14.         float rotation = Input.GetAxis("Horizontal") * lensRotationSpeed;
15.         rotation *= Time.deltaTime;
16.         transform.Rotate(0, -rotation, 0);
17.  
18.         //Light ray detection
19.         Debug.DrawRay(transform.position, transform.forward * debugRayLength, Color.red); //Debug code
20.  
21.     }
22. }
23.  

 

Ah, that makes sense. Thanks!