Turn off power to the circuit
Remove the fuse from its holder
Set a multimeter to continuity mode
Touch the probes to both ends of the fuse
Check for a beep or near-zero resistance
If there is no continuity, the fuse is blown
Set the multimeter to resistance mode if continuity mode is unavailable
Measure across the fuse and look for a very low reading
Inspect the fuse visually for a broken element or discoloration
Replace the fuse with one of the same type and rating if it is faulty