The fuse link is a short length of wire, integral with the engine compartment wiring harness and should not be confused with standard wire. The fusible link wire gauge is smaller than the circuit which it protects. Under no circumstances should a fuse link replacement repair be made using a length of standard wire cut from bulk stock or from another wiring harness.
Fusible link wire is covered with a special thick, non-flammable insulation. An overload condition causes the insulation to blister. If the overall condition continues, the wire will melt. To check a fusible link, look for blistering insulation. If the insulation is okay, pull gently on the wire. If the fusible link stretches, the wire has melted. Fusible links are usually located in the starting or charging system circuits.