Initial Inspection and Diagnostic Overview

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

VISUAL INSPECTION CHART

Mechanical
^ Switch(es)

Electrical
^ CJB Fuses:
- 7 (20 A)
- 32 (15 A)
- 39 (5 A)
^ Wiring harness
^ Connections
^ Lamps
^ Circuitry

4. If the concern remains after the inspection, connect the New Generation STAR (NGS) Tester to the Data Link Connector (DLC) located beneath the instrument panel and select the vehicle to be tested from the NGS menu. If the NGS does not communicate with the vehicle:
^ check that the program card is correctly installed.
^ check the connections to the vehicle.
^ check the ignition switch position.

5. If the NGS still does not communicate with the vehicle, review the New Generation STAR Tester manual.
6. Carry out the DATA LINK DIAGNOSTIC TEST. If the NGS responds with:
^ CKT914, CKT915 or CKT70=ALL ECUS NO RESP/NOT EQUIP, refer to Information Bus.
^ NO RESP/NOT EQUIP for GEM, go to Pinpoint Test A. A No Communication With the Generic Electronic Module
^ SYSTEM PASSED, retrieve and record the continuous Diagnostic Trouble Codes (DTCs), erase the continuous DTCs and carry out self-test diagnostics for the GEM.

7. If the DTCs retrieved are related to the concern, go to 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