Horn Switch: Testing and Inspection

Horn Switch Test

'09-11 models

NOTE: Check for a blown No. 7 (15 A) fuse in the under-hood fuse/relay box. If it is blown, check for a faulty horn relay.

1. Remove the steering column covers Steering Column Removal/Installation.

2. Disconnect the dashboard wire harness B 13P connector (A) from the cable reel (B).





3. Connect the dashboard wire harness B 13P connector terminals No. 1 and No. 13 with a jumper wire. The horns 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 B 13P connector.

5. Check for continuity between dashboard wire harness B 13P connector terminal No. 13 and body ground. There should be 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 (G401) or an open in the ground wire.

6. Measure the voltage between dashboard wire harness B 13P connector terminal No. 1 and body ground. There should be battery voltage.

- If there is battery voltage.
- Repair an open or high resistance in the wire between under-hood fuse/relay box connector D (14P) terminal No. 2 and horn.
- Faulty horn.
- Faulty horn relay.
- If there is no voltage.
- Repair an open or high resistance in the wire.
- Faulty horn relay.
- Faulty multiplex control unit; replace the under-dash fuse/relay box Under-Dash Fuse/Relay Box Removal And Installation.

7. Reconnect dashboard wire harness B 13P connector to the cable reel, then remove the driver's airbag assembly Driver's Airbag Replacement.

8. Connect the cable reel subharness 13P connector terminals No. 1 and No. 13 with a jumper wire. The horn should sound.

- If the horn sound, go to step 9.
- If the horn does not sound, an open or high resistance in the wire; replace the cable reel.

9. Disconnect the cable reel subharness 13P connector (A).






10. Check for continuity between terminal (A) and cable reel subharness 13P connector terminal No. 13. There should be continuity.

- If there is continuity, go to step 11.
- If there is no continuity.
- An open or high resistance in the wire, replace the cable reel subharness.
- Poor terminal (T151).





11. Check for continuity between cable reel subharness 13P connector terminal No. 1 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 Overhaul.
- If there is no continuity, repair an open or high resistance in the wire, or replace the cable reel subharness.