Old Tiny Traffic Light

Hello, I have an old auto accesory that is a small traffic light with the 3 colors: Green, Yellow and Red. These were used long time ago I guess as a third back-stop red light. The thing is that I really dont know how to make it work, so if someone knows or remebers how these traffic lights were connected, please let me know. It has 3 separate cables to make a connection but I dont know were to connect 2 of these cables and also how the green and yellow lights will work. I mean the red light is the easy one to connect. Thank You!