Friend,
You are not giving us much information to work off of. What shaft broke? Did you remove the turret to make the repair? What control is on the machine (I am assuming Fanuc)? Is the turret servo driven, or is the positioning done by proximity switches? What light are you referring to, as encoders dont have lights? Is it a turret clamp light on the operator panel? I swear I am not being a smart ass, but we REALLY need more information to point you in the right direction.