1. Visual Inspection: Look at the fuse. If the thin metal filament inside the fuse is broken or melted, the fuse is blown.
2. Test with a Multimeter: Set your multimeter to the continuity setting. Touch one probe to one end of the fuse and the other probe to the other end. If the meter displays a reading (usually a beep or a low resistance value), the fuse is good. If the meter displays an "OL" (open circuit) reading, the fuse is blown.
3. Check for Symptoms: If a particular electrical component in your car (like the headlights or the radio) is not working, check the corresponding fuse. If the fuse is blown, replacing it may solve the problem.