Check whether the device or circuit has suddenly stopped working
Inspect the fuse element for a visible break, gap, or burn mark
Look for discoloration, darkening, or cloudiness in the fuse body
Use a multimeter set to continuity mode to test for a complete circuit
Use a multimeter set to resistance mode to check for near-zero resistance
Compare the fuse to a known good fuse of the same type and rating
Check whether the fuse indicator, if present, shows it has blown
Verify that the fuse holder contacts are not loose, corroded, or damaged
Replace the fuse with the exact same type and rating if it appears faulty