Locate the fuse box on a Ford Focus by looking under the steering wheel, slightly to the left and below the dash by the brake pedal. There is a cover that hides the fuse box from view that someone must remove to access the fuses.
If a Ford Focus fuse blows, it results in one of the vehicle functions no longer working, such as the power windows, radio or high beams. To restore function, someone has to replace the fuse with one of equal amperage. There are handheld testers that can help people to determine, which fuse is bad so that they can replace the right one.