GUI.DrawTexture Not working with RenderTexture

Unity Engine
1

I have a fairly simple piece of code that I can’t seem to get to work right.

public class Crosshair : MonoBehaviour {
   
    public Texture crosshairTexture;
    Rect position;
    Camera MyCam;
    public Color defaultColor = Color.black;
   
    // Use this for initialization
    void Start () {
        MyCam = this.gameObject.camera;
    }

   void OnGUI () {
       float WidthRatio = (MyCam.pixelWidth / Screen.width);
       float HeightRatio = (MyCam.pixelHeight/Screen.height);
       float TextureWidth = crosshairTexture.width * WidthRatio;
       float TextureHeight = crosshairTexture.height * HeightRatio;
       this.position = new Rect(MyCam.pixelRect.xMin +((MyCam.pixelRect.width - TextureWidth)/2),
       Screen.height - (MyCam.pixelRect.yMin +((MyCam.pixelRect.height + TextureHeight)/2)), TextureWidth, TextureHeight);
       GUI.color = defaultColor;
        GUI.DrawTexture(position, crosshairTexture);
    }
}

When I pass in a Texture2D as the crosshairTexture, everything is perfect. When I pass in a renderTexture, nothing gets drawn to the screen.

No matter what I change in the settings for the render texture I either get nothing on the screen, or a black box. If I set the clear mode on the rendertexure Camera to skybox, I can get a VERY faint outline of some clouds.

2

Nothing?