The pulsing green glow that shows when a module is active is not distinct enough, especially given that the modules have a green bar across the top to start with. Pulsing means that you need to look at it long enough for it to pulse once to be sure as well. If you’re multi-boxing, it is pretty easy to miss, on a quick scan of a screen, that one of your ships has an inactive module that should be active, or vice versa. That isn’t true for modules with cycle times, since they also get the white line rotating around it, but for ones that don’t, it isn’t really a great UI.
I’d suggest doing something to make it starker. Maybe the glow orange or some other color not already in use in that part of the interface. Maybe the button changes color entirely. Something like that.