This procedure covers the replacement of the horn relay in a 2011-2014 Ford F-150 3.5L EcoBoost. The relay is located in the battery junction box under the hood.

Warnings

Tools required

Parts

• Horn relay × 1 — Motorcraft SW-6925 or equivalent mini relay

Preparation

1. Park vehicle on level ground and engage parking brake
2. Turn off ignition and remove key
3. Allow engine to cool if recently operated
4. Locate the battery junction box on the driver's side of the engine compartment near the battery

Procedure

1. 1

   Disconnect negative battery terminal
   Using a 10mm socket, loosen the negative battery terminal bolt and remove the cable from the battery post. Secure the cable away from the battery to prevent accidental reconnection.
   Torque spec

   Battery Terminal Bolts6 Nm (4 lb-ft)
2. 2

   Remove battery junction box cover
   Locate the battery junction box (BJB) on the driver's side of the engine bay. Release the retaining clips or tabs on the sides of the cover and lift the cover off. The fuse and relay diagram is printed on the underside of the cover.
3. 3

   Identify the horn relay location
   Using the diagram on the cover, identify the horn relay location. It is typically labeled as 'HORN' and is a mini relay (small square relay). Common locations are cavity R2.34 or R2.35, but verify with your specific diagram as relay positions may vary by production date and options.
4. 4

   Remove the old horn relay
   Using needle-nose pliers or a relay puller, grasp the horn relay firmly and pull straight up with steady pressure to remove it from the junction box socket. Avoid rocking the relay side to side as this can damage the socket terminals.
5. 5

   Inspect the relay socket
   Examine the relay socket terminals for corrosion, burns, or damage. The terminals should be clean and make firm contact. If corrosion is present, clean with electrical contact cleaner and allow to dry. If terminals are damaged or melted, the junction box may require professional repair.
6. 6

   Install the new horn relay
   Align the new horn relay with the socket, ensuring the orientation matches the diagram (relays are typically keyed and will only fit one way). Press the relay firmly into the socket until it is fully seated and flush with the other relays. You should feel it click into place.
7. 7

   Reinstall the junction box cover
   Place the cover back onto the battery junction box, ensuring all tabs and clips engage properly. Press down firmly around the perimeter until all clips are fully seated and the cover is secure.
8. 8

   Reconnect negative battery terminal
   Place the negative battery cable back onto the negative battery post. Thread the terminal bolt and tighten to specification using a torque wrench. Ensure the connection is clean and secure.
   Torque spec

   Battery Terminal Bolts6 Nm (4 lb-ft)

Reassembly

1. Verify the battery junction box cover is properly secured with all clips engaged
2. Ensure no tools or parts are left in the engine compartment
3. Reset clock and radio presets as needed

Verification

• Turn the ignition to the ON position without starting the engine
• Press the horn button on the steering wheel and verify the horn sounds properly
• If horn does not sound, verify relay is fully seated and in the correct cavity position
• Check that no warning lights are illuminated on the instrument cluster related to the battery or electrical system
• Test horn operation with engine running to confirm full functionality

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