IR Scope Attachment

Not sure if this is a bug, but here goes.
I got an IR Attachment, attached but nothing happens.
I thought maybe needs battery or some kinda toggle but nothing seems to make it work.
Anyone know how to use. Is there something more then just equipping it?

You need to press a button to change vision modes (just like with binoculars).

And you need to press the key while you are aiming. Then it will rotate through your vision modes.

More on this - I think its god awful as well as the nightvison.