There isn't a single "inline" component protecting the entire electrical system. If you're experiencing an electrical problem, you need to identify the specific circuit that's malfunctioning and then check the corresponding fuse or relay in one of the fuse boxes. Your owner's manual will have a diagram showing which fuse or relay controls what.
To find the fuse boxes:
* Underhood Fuse Box: This is the larger of the two and is usually located near the battery, often on the fender well or inner fender.
* Under-Dash Fuse Box/Panel: This is typically located under the dashboard, often near the steering column or on the driver's side.
Important Note: If you're not comfortable working with car electrical systems, it's best to consult a qualified mechanic. Incorrectly replacing fuses or relays can lead to further damage.