Horn Relay

This procedure covers the replacement of the horn relay in a 2014-2018 Chevrolet Silverado 1500 with the 5.3L V8 EcoTec3 engine, located in the underhood fuse/relay box.

Warnings

Tools required

Parts

• Horn relay × 1 — ACDelco D1780C or equivalent

Preparation

1. Park vehicle on level ground and turn off ignition
2. Allow engine to cool if recently operated to avoid contact with hot components
3. Locate the underhood fuse/relay center on the driver's side of the engine compartment near the battery
4. Identify the horn relay location using the diagram on the underside of the fuse box cover or owner's manual

Procedure

1. 1

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

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

   Remove fuse box cover
   Release the retaining tabs on the underhood fuse/relay center cover by pressing or pulling as designed. Lift the cover straight up and set aside in a clean location. Keep the cover's underside diagram visible for reference.
3. 3

   Locate horn relay
   Reference the fuse/relay diagram to identify the horn relay position. The horn relay is typically labeled as 'HORN' or 'HRN' and may be located among other mini relays in the fuse block. Note its orientation before removal.
4. 4

   Test old relay (optional)
   If diagnosing a horn issue, use a multimeter to test the relay terminals for continuity according to the relay pin diagram. This can confirm relay failure before replacement. Check for 12V power supply to the relay socket as well.
5. 5

   Remove failed horn relay
   Firmly grip the horn relay body and pull straight up with steady pressure to remove it from the socket. If resistance is encountered, gently rock the relay side-to-side while pulling upward. Avoid using excessive force that could damage the socket terminals.
6. 6

   Inspect relay socket
   Examine the relay socket terminals for corrosion, damage, or bent pins. Clean any corrosion with electrical contact cleaner if present. Ensure all socket terminals are straight and properly positioned to accept the new relay.
7. 7

   Install new horn relay
   Align the new horn relay with the socket, matching the orientation of the original relay. Ensure the relay pins align with the socket terminals. Press the relay firmly into the socket until it is fully seated and flush with surrounding relays.
8. 8

   Reinstall fuse box cover
   Position the fuse/relay center cover over the box, aligning all tabs and guides. Press down firmly until all retaining tabs click into place and the cover is fully seated.
9. 9

   Reconnect battery negative terminal
   Place the negative battery cable onto the negative battery post. Install and tighten the terminal bolt to specification using a 10mm socket. Ensure the connection is secure but do not overtighten.
   Torque spec

   Battery Terminal Bolts6 Nm (4 lb-ft)

Reassembly

1. Ensure fuse box cover is completely seated with all tabs engaged
2. Verify battery terminal connection is tight and secure
3. Reset clock and radio presets as needed

Verification

• Turn ignition to ON position without starting engine
• Press the horn button on the steering wheel to verify horn operation
• Confirm horn sounds properly with clear, full volume tone
• If horn still does not function, verify fuse condition and check horn switch and wiring
• Test horn multiple times to ensure consistent operation

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