I have had the same ponderings and I would love to find some sort of manual or data sheet. In the meantime the Green light means that it is working and at the set point. You can test that by turning the set point up and down and the green will go off and the red will come on. The red light means that it is working but is not cold enough to reach the set point. The orange light is a mystery - it is turned on /off by the switch next to it but I have yet to see any actual effect. Maybe it initiates a defrost cycle??
Tom
July 2014