A fusible link is a short piece of wire several gauge sizes smaller than the circuit it protects. It will melt in an overload situation, opening the circuit.

Your starter and other circuits have these fusible links. The size is printed on the insulation. If the insulation is burned beyond recognition, consult your GM dealer for the proper size. Replace a fusible link with one of the same size and insulation type. Fusible link insulation is a special purpose high-temperature material.

The hydraulic brake booster motor feed circuit and starter circuit are protected by a fusible link. Vehicles with a diesel engine have a fusible link for the intake heater feed circuit.