I recently purchased a bike that´s wof just ran out and took it for a new one. It failed due to the rear brake light not turning on when the front brake was applied. He said I needed to fix this or get a letter saying this bike didn´t come with one (brake switch light). I was wondering if something is missing on my bike - theres only one cable going to the front brake and theres nothing else - did this come standard ? Please help :(