2018 Ford F-150 Fuse Box Diagram & Amperage

Quick answer

The 2018 Ford F-150 has three main fuse box locations:

• Power Distribution Box (Under-hood): Located in the engine compartment, typically near the battery on the driver's side.
• Passenger Compartment Fuse Panel: Located behind a panel on the passenger-side kick panel.
• Rear Electronic Module (REM) Fuse Box: Located behind a panel on the driver's side in the rear cargo area/trunk.

Power Distribution Box (Under-hood)

This fuse box is located in the engine compartment, usually on the driver's side near the battery. It contains high-current fuses and relays for major electrical components.

Relay Locations (Under-hood):

• R1: Starter Relay
• R2: Fuel Pump Relay
• R3: PCM/ECM Relay
• R4: Blower Motor Relay
• R5: A/C Clutch Relay
• R6: Cooling Fan Relay 1
• R7: Cooling Fan Relay 2
• R8: Horn Relay

Passenger Compartment Fuse Panel

This fuse panel is located inside the cabin, typically behind a removable panel on the passenger-side kick panel. It controls various interior electrical components.

Rear Electronic Module (REM) Fuse Box

This fuse box is located in the rear of the vehicle, usually behind a panel in the driver's side cargo area or trunk. It typically handles power for rear-specific components.

How to test a fuse

Testing a fuse is a straightforward process that can help you diagnose electrical issues quickly. Here's how:

1. Safety First: Always turn off the ignition and remove the key before working with fuses. If working under the hood, disconnect the negative battery terminal to prevent accidental shorts.
2. Locate the Fuse Box: Refer to your owner's manual or the diagrams above to find the correct fuse box for the circuit you're troubleshooting.
3. Identify the Suspect Fuse: Look at the fuse box legend (usually printed on the inside of the fuse box cover) to identify the fuse associated with the malfunctioning component.
4. Visually Inspect the Fuse: Many modern fuses have a clear plastic body, allowing for a visual inspection. Look for a broken wire or a dark, burnt appearance inside the fuse. If it's blown, the metal strip connecting the two terminals will be visibly broken.
5. Use a Fuse Tester or Multimeter: For a more accurate test, use a fuse tester or a multimeter set to the continuity setting.
   • Fuse Tester: Simply touch the probes of the fuse tester to the two exposed test points on the top of the fuse. If the light on the tester illuminates, the fuse is good. If not, it's blown.
   • Multimeter: With the multimeter set to continuity (often indicated by an audible beep symbol), touch one probe to each metal terminal of the fuse. A good fuse will show continuity (multimeter beeps or displays a low resistance reading). A blown fuse will show no continuity or an "OL" (open circuit) reading.
6. Replace if Blown: If you confirm the fuse is blown, replace it with a new fuse of the exact same amperage rating and type. Using a fuse with a higher amperage can lead to serious electrical damage or fire.

Common blown fuses on this vehicle

While any fuse can blow, some are more commonly affected due to their high usage or connection to frequently accessed components.

• Cigar Lighter / 12V Power Outlets (Passenger Compartment F3): These fuses often blow due to overloading from charging multiple devices or using high-power accessories. If your phone charger or air compressor isn't working, check this first.
• Trailer Brake Controller (Under-hood F13, Rear F8): If you frequently tow or have issues with your trailer brakes, these high-amperage fuses can blow. Always ensure your trailer wiring is in good condition to prevent shorts.
• Headlights (Under-hood F7-F10): While less common with modern halogen or LED systems, a faulty bulb or wiring issue can still cause these fuses to blow. If one of your headlights is out, check its specific fuse.
• Radio/Infotainment System (Passenger Compartment F1): Issues with aftermarket installations, short circuits within the head unit, or even a sudden power surge can cause this fuse to blow, leading to a blank screen or no audio.
• Blower Motor (Under-hood F11): A failing blower motor, especially one working harder due to a clogged cabin air filter, can draw excessive current and blow its fuse. If your A/C or heat fan isn't working, this is a likely culprit.

What to check first:

1. Verify the Symptom: Make sure the component is truly not working. Sometimes it's a simple user error or a different problem.
2. Check the Associated Fuse: Go directly to the fuse specified for that component in the tables above. Visually inspect it first.
3. Owner's Manual: Always double-check your owner's manual for the most accurate and up-to-date fuse box diagrams and specific locations for your trim level, as there can be minor variations.

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