I'm new to electric bikes so please bare with me if I ask a simple question! I have a Banfang BBS02 with the C961 controller. I've set the backlight brightness to #5 but I'm wondering when the backlight is supposed to come on. I believe when it gets dark outside while riding the backlight comes on but I've tried it inside the garage with the lights out and motor running and nothing happens? Is it automatic or what?