Important: The following steps must be completed before using the symptom tables.
- Perform the Body Control Module (BCM) Diagnostic System Check
before using the Symptom Tables in order to verify that all of the following
    are true:
 
| •  | The control module(s) can communicate via the serial data link. | 
 
- Review the system operation in order to familiarize yourself with
the system functions. 
 
Refer to 
Body Control System Operation 
.
Visual/Physical Inspection
|     •  | Inspect the easily accessible or visible system components for
obvious damage or conditions which could cause the symptom. | 
 
Intermittent
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 the symptom: