These strip fuses can fail in at least a couple of different ways.

  1. The metal can become brittle with age and develop a hairline fracture. This kind of failure can be impossible to see until the fuse is removed and falls into pieces.
  2. As with all fuses, excess current can cause the fuse to 'blow'. A blown fuse is always indicative of an electrical problem so be sure to find the cause before you replace the fuse.

For safety, remove the negative terminal of the battery while working on the fuses.