Occasionally I run into a problem when using my selector switch. Sometimes the light does not come on when switching the selector to semi. Also, sometimes the selector will work in semi, however it will not go to full auto, it is like there is something blocking the selector between semi and full auto. I have noticed that if you remove the mag and invert the empty mag well towards a light source, this seems to correct the problem. Could it be that the sensor is just dirty? I have not seen where the eye is to clean it. Could it be a completely different issue?
Celcius CTW forum