The fuse is the most common method of automotive wiring circuit protection. Whenever there is an excessive amount of current flowing through a circuit the fusible element will melt and create an open or incomplete circuit. Fuses are a "one time" protection device and must be replaced each time the circuit is overloaded. To determine if a fuse is blown, remove the suspect fuse and examine the element in the fuse for a break. If the element is broken, replace the fuse with one of equal current rating.