Important: The following steps must be completed before using the symptom tables.
- Perform the
Diagnostic System Check - Lighting Systems 
 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. | 
 
- Review the system operation in order to familiarize yourself with
the system functions. Refer to the following:
 
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. | 
 
|     •  | If only one lamp is inoperative, inspect and repair a poor connection
or an open in the power feed or ground circuit before replacing the light
             bulb. Refer to 
Circuit Testing 
            and  
Wiring Repairs 
 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: