Horn Switch: Testing and Inspection

Horn Switch Test

NOTE:

- SRS components are located in this area. Review the SRS component locations Locations, and precautions and procedures Service and Repair before doing repairs or servicing.
- Before testing, check the No. 24 (10 A) fuse in the under-dash fuse/relay box. If the fuse is blown, repair a short to ground in the No. 24 (10 A) fuse circuit.

1. Remove the steering column covers Service and Repair.

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






3. Connect dashboard wire harness 20P connector terminal No. 1 and No. 2 with a jumper wire. The horn should sound.

- If the horn sounds, go to step 7.

- If the horn does not sound, go to step 4.

4. Remove the jumper wire from the dashboard wire harness 20P connector.

5. Check for continuity between dashboard 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 an open or high resistance in the wire, or poor ground (G502).

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, check these items. If OK, faulty MICU. Replace the under-dash fuse relay box (USA model Under-Dash Fuse/Relay Box Removal and Installation (USA Models), Canada model Under-Dash Fuse/Relay Box Removal and Installation (Canada Models)).
- Faulty horn.

- If there is no battery voltage, check for continuity between under-dash fuse/relay box connector Q (16P) terminal No. 11 and cable reel subharness 20P connector terminal No. 1. If there is continuity, faulty MICU. Replace the under-dash fuse/relay box (USA model Under-Dash Fuse/Relay Box Removal and Installation (USA Models), Canada model Under-Dash Fuse/Relay Box Removal and Installation (Canada Models)).

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

8. Connect cable reel subharness 20P connector terminals No. 11 and No. 12 with a jumper wire. The horn should sound.

- If the horn sounds, go to step 9.

- If the horn does not sound, replace the cable reel Service and Repair.

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






10. Check for continuity between ground terminal (G551) 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, check for:
- An open or high resistance in the wire, replace the cable reel subharness.





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 and the horn switch plate or replace the driver's airbag.

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