Protection of some circuits is carried out by including fusible links in their electrical circuit. Inserts are usually used to protect non-fused circuits such as the ignition circuit.
Fuses on these models are similar to fuses in the sense that their failure (reflow) easily determined visually.
To replace the fuse, first disconnect the negative cable from the battery. Remove the burnt insert and install a new one in its place (can be purchased at a dealership or auto accessories store). Before replacing an insert, always try to determine the cause of the overload that caused it to fail.