I have just disassembled a RC car (a BBR 1:18 Scale Ferrari Enzo from 2005). Attached to the stepper motor that controls the steering of the car was a small circuit board with a cog wheel attached to it. I am trying to figure out what this circuit does. My idea is that it is responsible of keeping track of the wheels position but I am not certain. Here is a picture of it:
As you can see there are 5 wires coming out of it and I know that the green one is GND. Does anyone have an idea of what its function might be?