Fuel Pump Relay

Replace the fuel pump relay located in the engine compartment fuse box to restore proper fuel pump operation.

Warnings

Tools required

Parts

• Fuel pump relay × 1 — Motorcraft DY-1247 or equivalent micro relay 25A

Preparation

1. Park vehicle on level ground, shift to Park, engage parking brake, and turn off ignition
2. Allow engine to cool if recently operated to prevent burns from hot components
3. Locate owner's manual or fuse diagram to confirm fuel pump relay location in power distribution box
4. Gather all tools and replacement relay before beginning work
5. Verify replacement relay matches exact amperage and part specification (25A micro relay typical for 2015-2020 F-150 5.0L)

Procedure

1. 1

   Disconnect battery negative terminal
   Open the hood and secure with prop rod. Locate the battery in the engine compartment. Using a 10mm socket, loosen the negative (-) battery terminal bolt. Remove the negative cable from the battery post and position it away from the terminal to prevent accidental reconnection during the procedure.
   Torque spec

   Battery Terminal Bolts8 Nm (6 lb-ft)
2. 2

   Locate the power distribution box
   The power distribution box (fuse/relay box) is located on the passenger side of the engine compartment, mounted to the fender apron near the battery. It is a black plastic box with multiple electrical connectors entering from below.
3. 3

   Open the power distribution box cover
   Press the release tabs on both sides of the power distribution box cover and lift upward to remove. The cover contains a relay/fuse diagram on the underside. Set the cover aside in a clean area where it will not be damaged.
4. 4

   Identify the fuel pump relay
   Locate the fuel pump relay using the diagram on the cover or owner's manual. On 2015-2020 F-150 models, the fuel pump relay is typically labeled as relay R10 or R12 depending on model year. It is a micro relay (smaller than standard relays) with 25A rating. Verify by checking the relay label and position.
5. 5

   Remove the old fuel pump relay
   Using a relay puller tool or needle-nose pliers, grasp the fuel pump relay firmly at the base. Pull straight upward with steady pressure to extract the relay from its socket. Avoid rocking or twisting which can damage the socket terminals. Inspect the removed relay for signs of burning, melting, or corrosion which indicate electrical problems.
6. 6

   Inspect relay socket and terminals
   Use a flashlight to inspect the relay socket terminals inside the power distribution box. Look for corrosion, burning, discoloration, or bent pins. If corrosion is present, clean with electrical contact cleaner and allow to dry completely. If terminals are burned or melted, the entire power distribution box may require replacement - consult a professional technician.
   ⚠Damaged or burned socket terminals indicate an underlying electrical fault. Installing a new relay without addressing the root cause will result in repeated failure.
7. 7

   Install the new fuel pump relay
   Remove the new relay from packaging and verify it matches the removed relay in size, pin configuration, and amperage rating. Align the relay pins with the socket, ensuring correct orientation (relays are keyed and will only fit one way). Apply light dielectric grease to pins if desired. Push the relay firmly into the socket until it seats completely flush with the mounting surface. The relay should click into place and sit level with adjacent relays.
8. 8

   Reinstall power distribution box cover
   Position the cover over the power distribution box, aligning the cover tabs with the box slots. Press down firmly on all corners until the cover clicks into place and sits flush. Verify the cover is fully seated and latched on both sides.
9. 9

   Reconnect battery negative terminal
   Position the negative battery cable over the negative battery post. Install the terminal bolt and tighten to specification using a 10mm socket and torque wrench. Ensure the connection is clean and tight with no movement when tested by hand.
   Torque spec

   Battery Terminal Bolts8 Nm (6 lb-ft)

Reassembly

1. Verify all electrical connections are secure and no tools remain in engine compartment
2. Close hood and ensure it latches properly
3. The engine control module will need to relearn fuel system parameters during the first few minutes of operation

Verification

• Turn ignition to ON position (do not start engine) and listen for fuel pump priming for 2-3 seconds - a quiet whirring sound from rear of vehicle indicates pump is receiving power
• Check instrument cluster for any warning lights or messages related to fuel system
• Start the engine and verify it starts normally within expected cranking time (2-4 seconds typical)
• Allow engine to idle for 2-3 minutes and verify smooth operation without stumbling or hesitation
• Turn engine off, wait 30 seconds, then restart to verify fuel pump relay cycles properly on multiple start attempts
• With engine running, verify no burning smell or smoke from power distribution box area
• Test drive vehicle briefly to confirm normal acceleration and no fuel delivery issues under load

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