The brake light of your vehicle is not working. What could be the cause of this?

Your answer is correct. In German traffic rules, if the brake light is not working, common causes include a defective fuse or a defective bulb, since these directly affect the electrical circuit of the brake light. The brake fluid level, although important for the braking system's function, does not influence whether the brake light illuminates. Understanding that the brake light operates electrically helps you identify that issues with fuses or bulbs are the primary reasons for malfunction. This knowledge will help you troubleshoot brake light issues correctly in the future.