Important Preliminary Checks Before Starting: Perform
Diagnostic System Check - Horns
before using the symptom tables in order to verify that all of the following are
true:
| • | The body control module (BCM) can communicate via the serial data link. |
Visual/Physical Inspection
Several of the symptom procedures ask for a careful visual/physical check. This
step is extremely important, it could lead to correcting a problem without further
checks and can save valuable time. These checks include the following:
| • | Inspect the easily accessible or visible system components and harness
connectors for obvious damage or conditions which could cause the symptom. |
| • | Perform the following If a horn buzzes or has a harsh tone: |
| • | Inspect for debris in the joint where the horn fastens to the vehicle. |
| • | Test the torque of the horn mounting hardware. The horn mounting hardware
should be tightened to a torque of 10 N·m (7 lb ft). |
Intermittents
Faulty electrical connections or wiring may be the cause of intermittent conditions.
Refer to
Testing for Intermittent Conditions and Poor Connections
in Wiring Systems.
Symptom List
Refer to a symptom diagnostic procedure from the following list in order to
diagnose a symptom that does not set a DTC:
