I have this same doodad on my dash. It fell apart. and Im 800 miles from home.
I havent noticed anything detrimental going on but the bulb that is handled by the dash light switch is working. I assume thats for illumination. the yellow diode is unlit so I am assuming the OD is ON. WHich is where I want it for now.
Once I get home in a couple days, I'd like to replace the switch. But for now I want to make sure the OD is functioning.