1. Under the Hood: This fuse box usually handles higher-amperage circuits related to engine components and lighting. The cover of this fuse box *should* have a diagram printed on the inside of the lid showing which fuse controls what. If it's faded or missing, your owner's manual will have a more detailed diagram.
2. Inside the Car: There's usually a smaller fuse box inside the car, often located in the dashboard (typically near the steering column or on the side of the dash). This box controls interior lights, power windows, radio, etc. Similar to the under-hood box, the inside cover *should* have a diagram. Again, the owner's manual will be the definitive guide.
How to find out without the diagram (last resort):
If both diagrams are missing or illegible, you'll need to use a process of elimination. This is risky, and you could damage your car's electrical system if done improperly. Proceed with caution.
* Start with the owner's manual: The manual is your best friend. Even if the diagrams in the fuse boxes are unreadable, the manual will likely have a comprehensive fuse chart.
* Use a multimeter: If you're comfortable with basic electrical testing, a multimeter can help identify which circuit a fuse is protecting. You can test the voltage at the component (e.g., headlights, radio) *before* and *after* removing the suspect fuse. Remember to disconnect the negative battery terminal before doing any multimeter testing.
* Test one at a time: Never remove multiple fuses simultaneously. Only remove one fuse at a time, noting its location and amperage. Then, check if the associated component is inoperative. Put it back in and try another. Be very methodical.
* Online resources: Search for "1999 Ford Mustang GT fuse box diagram" online. Many websites and forums dedicated to Ford Mustangs might have downloadable diagrams or photos.
Important Note: If you're not comfortable working with car electrical systems, it's best to take your Mustang to a qualified mechanic to identify and replace the blown fuse. Improper fuse replacement can lead to further damage.
