Intermittent Horn Operation/Horn Inoperative (Inspect Horn System Components and Rewire Horn Circuit, If Necessary)

Some customers may comment on intermittent horn operation when pushing the horn pad or that the horn is inoperative.

The cause of this condition may be due to high ground resistance from the BCM through the multifunction switch, cancel cam and SIR module horn pad.

Verify that the horn operates using the key fob red alarm button. Check all the components in the horn system ground circuit. If no components are faulty, then rewire the horn circuit around the BCM using the procedure listed below.

1. Open the hood and locate the underhood fuse center on the right/passenger side shock tower.
2. Lift the cover for the underhood fuse center.
3. Locate and remove the SIR fuse (#9) from the underhood fuse center.
4. Remove the left/driver sound insulator panel from the IP.
5. Remove the CPA from the steering wheel module coil yellow connector. Disconnect the connector.
6. Disengage the data link connector (DLC) retainers. Remove the DLC from the IP.
7. Use a plastic tool to remove the ignition switch bezel.
8. Pull the IP accessory trim plate rearward slightly for access to the steering column filler.
9. Remove the steering column filler panel screws and remove panel from the IP.
10. Remove the inflatable restraint steering wheel module using the J 44298.
11. Inspect the SIR ground wire white plastic sleeve for proper installation in the cancel cam plastic tower (not bent over). It should also have been locked into place at the cancel cam post. Also, make sure the wire end cap was installed correctly so the flat end is correctly contacting the cancel cam surface.
12. Remove the steering wheel using the J 1859-A and J 42578.
13. Remove the tilt lever.
14. Remove the upper and lower steering column covers.
15. Remove the tie straps from the steering wheel wire harness.
16. Remove the SIR coil retaining ring.
17. Remove the SIR coil from the steering shaft.
18. Remove the wave washer.
19. Compress the steering shaft upper bearing spring and remove the lock ring using the J 23653-SIR and J 42137.
20. Remove the cam plate and cancel cam.
21. Inspect the cancel cam horn ring surface for any unusual wear on both sides. Inspect the copper colored horn contact pin on the multifunction switch for a rough surface. It should only be replaced if it is rough or worn. If it is rough, the cancel cam surface may be scored and it could also need replacing. Also, inspect the pin to assure smooth operation as you cycle it in and out. If the pin is OK, clean it off prior to reassembly.
22. If there appears to be excessive amount of grease on the cancel cam, you can remove grease, but there needs to be some grease on both sides of the cancel cam to prevent accelerated wear or noise from the multifunction switch pin and the SIR module ground wire. In some cases, there may be noise that develops when turning the steering wheel if there is not enough grease.
23. Reinstall the cancel cam and cam plate.
24. Reinstall the lock ring onto the steering shaft.
25. Compress the cam plate using the J 23653-SIR and J 42137.
26. Firmly seat the lock ring into the groove on the steering shaft assembly.
27. Remove the J 23653-SIR and J 42137.
28. Reinstall the wave washer.
29. Reinstall the SIR coil onto the steering shaft.
30. Reinstall the SIR coil retaining ring.
31. Install new tie straps to the steering wheel wire harness.
32. Reinstall the upper and lower steering column covers.
33. Reinstall the tilt lever.
34. Reinstall the steering wheel.
35. Reinstall the inflatable restraint steering wheel module.
36. If no faults were found with the above components, then perform the following steps to rewire the horn circuit around the BCM.

36.1.

On the BCM, disconnect the C1 and C3 connectors.

36.2.

On the C3 connector, locate cavity 9 (circuit 738, brown wire) and cut the wire just before the terminal (leaving the terminal in the cavity).

36.3.

Remove the insulation from circuit 738 wire end.

Important: Circuit 28 must remain intact going into the BCM and to the BEC.

36.4.

On the C1 connector, locate cavity 4 (circuit 28, black wire) and approximately 25 mm (1 in) up from terminal, remove the wire insulation.

36.5.

Run the circuit 738 wire to the circuit 28 wire and splice together using a splice clip. Tape the repair area.

36.6.

Connect the C1 and C3 connectors to the BCM.

37. Reinstall the steering column filler panel and screws.
38. Reinstall the ignition switch bezel.
39. Reinstall the DLC to the IP.
40. Connect the steering wheel module coil yellow connector and reinstall the CPA.
41. Reinstall the left/driver sound insulator panel to the IP.
42. Reinstall the SIR fuse (#9) to the underhood fuse center.
43. Close the cover on the underhood fuse center.
44. Close the hood.

For vehicles repaired under warranty, use: