Flow of Diagnosis

1. The interior lighting system is controlled by a Generic Electronic Module (GEM).
2. Verify the customer concern by operating the interior lamps.
3. Visually inspect for obvious signs of mechanical and electrical damage.

VISUAL INSPECTION CHART

Mechanical
^ Switch(es)

Electrical
^ Fuse(s)
^ Damaged wiring harness
^ Loose or corroded connector(s)
^ Circuitry
^ Bulb(s)

4. If the concern remains after the inspection, connect the New Generation STAR (NGS) Tester to the data link connector located beneath the instrument panel and select the vehicle to be tested from the NGS menu. If NGS Tester does not communicate with the vehicle:
^ Check that the program card is properly installed.
^ Check the connections to the vehicle.
^ Check the ignition switch position.
5. If NGS Tester still does not communicate with the vehicle, refer to the New Generation STAR Tester manual.
6. Perform the DATA LINK DIAGNOSTIC TEST. If the NGS Tester responds with:
^ CKT914, CKT915 or CKT70 = ALL ECUS NO RESP/NOT EQUIP, refer to Information bus.
^ NO RESPONSE/NOT EQUIPPED for Generic Electronic Module (GEM), go to Pinpoint Test J. J No Communication With the Module - GEM
^ SYSTEM PASSED, retrieve and record the continuous (DTCs), erase the continuous DTCs and perform self-test diagnostics for the GEM.
7. If the DTCs retrieved are related to the concern, go to the GEM DTC Index to continue diagnostics. Diagnostic Trouble Code Tests and Associated Procedures
8. If no DTCs related to the concern are retrieved, proceed to Symptom Chart to continue diagnostics. Symptom Related Diagnostic Procedures