electrical
Horn Relay
for 2017 Toyota Corolla 1.8L I4 · FWD
Difficulty
Easy
Time
12 min
Tools
4
Steps
6
Replace the horn relay located in the engine compartment fuse/relay box to restore horn operation.
Warnings
⚠Disconnecting the battery will erase radio presets and may require window auto-up/down relearn procedure
ℹ️Horn relay is typically in the engine compartment relay box, not the interior fuse box
Tools required
Relay puller or needle nose pliers
10mm socket
Ratchet
Flashlight
Parts
- Horn relay × 1 — 90987-02028 or equivalent
Preparation
- Park vehicle on level surface and engage parking brake
- Turn ignition to OFF position and remove key
- Allow engine to cool if recently operated
- Locate the engine compartment fuse/relay box on driver's side near battery
Procedure
- 1Open engine compartment relay boxLocate the black fuse/relay box on the driver's side of the engine compartment. Press the tab(s) on the box cover and lift upward to remove the cover. The relay diagram is typically printed on the underside of the cover.
- 2Identify horn relay locationRefer to the relay diagram on the cover underside to locate the horn relay position. The horn relay is typically labeled 'HORN' and is usually a small black cube-shaped relay. Note the orientation of the relay before removal.
- 3Remove old horn relayGrasp the horn relay firmly and pull straight upward to remove it from the socket. If difficult to grip, use a relay puller or needle nose pliers. Rock gently side-to-side while pulling if resistance is encountered, but do not bend the terminals.
- 4Inspect relay socketExamine the relay socket for corrosion, damage, or debris. Check that all terminal contacts are clean and not pushed back. If corrosion is present, clean terminals with electrical contact cleaner and allow to dry completely before proceeding.
- 5Install new horn relayAlign the new relay with the socket, ensuring correct orientation by matching the tab or notch on the relay base with the socket. Press the relay firmly into the socket until it is fully seated and sits flush with surrounding relays.
- 6Reinstall relay box coverPosition the relay box cover back onto the relay box, ensuring it is properly aligned. Press down firmly until all tabs click into place and the cover is completely secured.
Reassembly
- Ensure relay box cover is fully latched to prevent water intrusion
- No battery disconnect was required, so no relearn procedures are necessary
Verification
- Turn ignition to ON position without starting engine
- Press the horn button on the steering wheel and verify horn sounds clearly
- Test horn multiple times with short and long presses to confirm consistent operation
- If horn still does not work, verify horn fuse is intact and check horn electrical connections at the horn itself