2021 Ford F-150 — Fuse Box Diagram & Amperage

Quick answer

• Under-hood: Power Distribution Box (engine compartment, passenger side near the battery). Contains most high‑current fuses and several relays (starter, cooling fan, A/C clutch, trailer tow, headlamps, ABS).
• Passenger compartment: Fuse panel behind the right kick panel (lower dash, passenger side). Handles interior electronics (blower motor, radio/SYNC, airbags, power outlets/cigar lighter, wipers, lighting, ignition feeds).
• Rear/trunk/cargo: Not applicable on the 2021 F‑150 (no dedicated rear fuse panel). Trailer tow fuses/relays are in the under‑hood Power Distribution Box.

Note: Ford revised fuse layouts during the 2021 model year. The most common configuration is shown below, but you must verify against the printed legend on your fuse box lid and your owner’s manual for your exact trim/engine.

Under-hood Power Distribution Box (engine compartment)

Location: Passenger side of the engine bay, adjacent to the battery. Release the two locking tabs and lift the cover to access the fuses and relays.

The table lists the most commonly used circuits on 2021 F‑150. Exact fuse numbers and amperages vary by trim, equipment (LED vs. halogen lamps, trailer package, Pro Power Onboard, hybrid), and build date. Always confirm the fuse number and rating on the lid diagram before replacing anything.

Common relay positions inside the under-hood box (verify on lid):

• Starter relay: in the PDB, feeds the starter solenoid during crank.
• A/C clutch relay: in the PDB, engages the compressor when commanded.
• Cooling fan relay(s) or solid-state drivers: in/near the PDB depending on engine.
• Headlamp relays or solid-state lighting drivers (varies by halogen/LED).
• Trailer tow relays/drivers: integrated in the PDB on tow-package trucks.
• Fuel pump relay: integrated; on many 2021 trucks the fuel pump is controlled by a module—no separate serviceable relay.

Passenger compartment fuse panel (right kick panel)

Location: Behind the trim panel at the passenger-side kick panel (right side footwell). Pull back the weatherstrip, pop off the side trim, then remove the small access cover to reach the panel. A fuse puller is often clipped to the panel.

Notes:

• Many 2021 F‑150 functions are controlled by the Body Control Module (BCM) using solid-state drivers. Some circuits that used to have relays are now protected/controlled electronically; there may be no serviceable relay for those functions inside the cab.
• Hybrid/PowerBoost models and trucks with Pro Power Onboard add additional fusing that may not be serviceable by the owner. Consult the owner’s manual for those systems.

How to test a fuse

• Visual check: With the key off, pull the suspected fuse using the puller. Hold it to the light—if the metal link is melted or broken, the fuse is blown. Note that micro fuses can look intact but still be open.
• Test light method: Leave the fuse installed, turn the circuit ON, and probe the two test tabs on top of the fuse. A good fuse lights the test light on both tabs; power on only one tab means the fuse is blown. No power on either tab points to a supply issue or key/circuit not active.
• Multimeter continuity: Remove the fuse and set your meter to continuity/ohms. A good fuse reads near 0 ohms or beeps; OL/infinite means open.
• Always match the amperage: Replace only with the same amp rating shown on the fuse and printed on the lid. If it blows again immediately, find and fix the shorted component or wire instead of upsizing the fuse.

Common blown fuses on this vehicle (what to check first)

• Cigar lighter/12V power points: These often pop when phone chargers, air pumps, or older accessories short. Inspect the socket for coins/debris, try a different charger, and check the dedicated power point fuses in the passenger panel. Some trucks have separate fuses for each outlet.
• Trailer tow lighting: Trailer left/right turn/stop and running-lamp fuses in the under‑hood box commonly blow due to trailer wiring shorts or corroded 7‑way connectors. Unplug the trailer, replace the blown fuse, and re‑test. If the fuse holds with the trailer unplugged, repair the trailer harness/lamps.
• Headlamps/parking lamps: A failed bulb or moisture in a lamp housing can short the circuit. Verify bulb condition and lamp housings before replacing fuses.
• Blower motor: A seizing blower motor or shorted resistor/module can pop the HVAC fuse. Listen for noisy or stiff blower operation. If the new fuse blows instantly, test blower current draw and inspect the harness at the blower connector.
• Fuel pump/PCM: Rare, but if the engine stalls/no-start and the fuel pump or PCM fuse is open, check for rodent damage, chafed wiring over the tank/left frame rail, or water intrusion at connectors before replacing parts.
• ABS: The high‑current ABS pump fuse can blow after a pump motor short. Scan for ABS codes; don’t just replace the fuse repeatedly—diagnose the hydraulic control unit and wiring.

Tips:

• Ford altered fuse numbering within the 2021 model year. If your truck’s fuse numbers don’t match an online chart, trust the map inside your lid.
• Many lighting and powertrain outputs are solid‑state. If a circuit is dead and the fuse is good, a scan of the BCM/PCM for DTCs can save time.

Always verify against the diagram printed inside your fuse box lid and your owner’s manual. Replace fuses with the exact same amperage.

Find a trusted shop on Repairius.