The answer to 'how to test fuse box' is to visually inspect the fuse box, test each fuse with a multimeter, and check for any signs of damage or wear. This will help identify any blown or faulty fuses that need to be replaced.
First, turn off the main power to the fuse box and open the cover. Carefully examine each fuse for any signs of discoloration, cracks, or other damage. Then, use a multimeter to test the continuity of each fuse. If a fuse shows no continuity, it is blown and needs to be replaced. You can also test the fuse by removing it and checking if the metal strip inside is intact.