Response from LEGO SHOP
11. september 2018
Emily, Customer ServiceThanks for your review! The LEGO® Power Functions Rechargeable Battery Box features a speed control mechanism on the front. When used with the Power Functions Light, the speed control turns into a brightness control. So if your Battery Box is set to the lowest speed, the lights won't shine. Turn up the speed, and the lights will gradually become brighter. If that doesn't do the trick, then you can get in touch with our Customer Service team at LEGO.com/Service.