Multimeters are devices used to measure voltage, resistance, and current in an electrical circuit. They can be used to test car fuses by checking the continuity of the circuit with the fuse installed. First, set the meter to measure continuity (which will usually look like an audible tone). If the meter beeps when touching both ends of the fuse, then it is in good condition. However, if the meter does not sound, then the fuse may be bad and require replacement.