Horn Switch: Testing and Inspection

Horn Switch Test

NOTE: Check for a blown No 10 (20 A) fuse in the under-hood fuse/relay box. If it is blown, check for a faulty horn relay (built in the relay circuit board).. Testing and Inspection

1. Remove the steering column covers. Service and Repair

2. Disconnect the dash board wire harness 20P connector (A) from the cable reel (B).

3. Connect dash board wire harness 20P connector terminals No. 1 and No. 2 with a jumper wire. The horns should sound.
- If the horns sound, go to step 7.

- If the horns don't sound, go to step 4.

4. Remove the jumper wire from the horn switch 20P connector.

5. Check for continuity between dash board wire harness 20P connector terminal No. 2 and body ground. There should continuity.
- If there is continuity, go to step 6.

- If there is no continuity, repair open in the wire, or poor ground (G501).

6. Measure the voltage between dashboard wire harness 20P connector terminal No. 1 and body ground. There should be battery voltage.
- If there is battery voltage, replace the horns.

- If there is no battery voltage, repair an open in the wire, or faulty driver's MICU; replace the driver's under-dash fuse/relay box.

7. Reconnect dashboard wire harness 20P connector to the cable reel, then remove the driver's airbag assembly. Driver's Airbag Replacement

8. Connect cable reel subharness 20P connector terminals No. 11 and No. 12 with a jumper wire. The horns should sound.
- If the horns sound, go to step 9.

- If the horns don't sound, repair open in the wire, or replace the cable reel. Service and Repair





9. Disconnect the cable reel subharness 20P connector (A).






10. Check for continuity between terminal (T9) and cable reel subharness 20P connector terminal No. 12. There should be continuity.
- If there is continuity, go to step 11

- If there is no continuity.
- Open in the wire, replace the cable reel subharness.

- Poor terminal (T9).

11. Check for continuity between cable reel subharness 20P connector terminal No. 11 and horn switch positive terminal 1P. There should be continuity.
- If there is continuity, check or adjust the installation of the driver's airbag assembly and the horn switch plate or replace the driver's airbag assembly.

- If there is no continuity, repair open in the wire, or replace the cable reel subharness.