The fuse is the most common method of an 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 open, remove the suspected fuse and examine the element in the fuse for an open (2). If not broken (1), also check for continuity using a Digital Multi Meter or a Test Light. If the element is open or continuity is suspect, replace the fuse with one of equal current rating.
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