Diagnosis And Testing - Horn Switch
To avoid serious or fatal injury on vehicles equipped with airbags, disable the Supplemental Restraint System (SRS) before attempting any steering wheel, steering column, airbags, airbag curtains, knee blocker, seat belt tensioner, impact sensor or instrument panel component diagnosis or service. Disconnect the Intelligent Battery Sensor (IBS)/negative battery cable assembly from the negative battery post, then wait two minutes for the system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the SRS. Failure to take the proper precautions could result in accidental airbag deployment.
Refer to the appropriate wiring information. The wiring information includes wiring diagrams, details of wire harness routing and retention, connector pin-out information and location views for the various wire harness connectors, splices and grounds. For proper wire repair, and connector repair procedures. Refer to STANDARD PROCEDURE . and. Refer to REMOVAL . Refer to INSTALLATION .
- Remove the Driver Air Bag (DAB) from the steering wheel. Refer to AIR BAG, DRIVER, REMOVAL AND INSTALLATION .
- Disconnect the steering wheel wire harness connector from the horn switch connector.
- With the horn switch contacts released, check for continuity between the two terminals in the horn switch connector. There should be no continuity. If OK, go to Step 4 . If not OK, replace the DAB.
- With each of the horn switch contacts pressed one at a time, check for continuity between the two terminals in the horn switch connector. There should now be continuity. If OK, go to Step 5 . If not OK, replace the DAB.
- Check the ground circuit between the horn switch and Steering Column Control Module (SCCM) for continuity. If OK, go to Step 6 . If not OK, repair the open ground circuit or replace the SCCM as required.
- Check the internal ground circuit of the SCCM for continuity to ground from the horn switch connector receptacle on the SCCM to chassis ground. If OK, go to Step 8 . If not OK, go to Step 7 .
- Check the SCCM ground circuit to chassis ground for continuity from the SCCM connector to chassis ground. If OK, replace the SCCM. If not OK, repair the SCCM ground circuit for an open.
- Check the horn switch sense circuit between the SCCM and the Body Control Module (BCM) for shorts or opens. Repair the shorted or open circuit.