Interior Lighting

1. The interior lighting system is a GEM/CTM controlled system.

NOTE: The Generic Electronic Module (GEM)/Central Timer Module (CTM) must be reconfigured upon replacement. Refer to the New Generation STAR (NGS) Tester help screen on the configuration card to program the tire size and axle ratio.

2. Verify the customer concern by operating the system in question.
3. Visually inspect for obvious signs of mechanical and electrical damage.

VISUAL INSPECTION CHART

Mechanical
^ Switch(es)

Electrical
^ Fuse(s) 1 (60 A), 25 (7.5 A), 26 (10 A), and 10 (7.5 A)
^ Damaged wiring harness
^ Loose or corroded connections
^ Lamp(s)
^ Circuitry

4. If the concern remains after the inspection, connect the 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 properly installed.
^ check the connections to the vehicle.
^ check the ignition switch position.
5. If the NGS still does not communicate with the vehicle, refer to the New Generation STAR Tester manual.
6. Carry out the DATA LINK DIAGNOSTIC TEST. If the NGS responds with:
^ CKT 914, CKT915 or CKT70=ALL ECUS NO RESP/NOT EQUIP, refer to Information Bus.
^ NO RESP/NOT EQUIP for GEM/CTM, go to Pinpoint Test A. A No Comm With the GEM or CTM 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/CTM.

7. If the DTCs retrieved are related to the concern, go to the GEM/CTM DTC Index to continue diagnostics. GEM/CTM Diagnostic Trouble Code (DTC) Index
8. If no DTCs related to the concern are retrieved, proceed to Symptom Chart to continue diagnostics. Interior Lighting