Troubleshooting Hints - Interior Lights Dimming

PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS
1. If only one lamp does not operate or dim, check bulb, socket and related wiring (see schematic).
2. Check I/P Bussed Electrical Center (BEC) HUD Fuse by visual inspection.
3. Check that grounds G201 and G202 are clean and tight.
4. If the Radio VF display is inoperative, refer to Audio Systems for electrical schematics and diagnosis. Radio, Stereo, and Compact Disc
5. If the HVAC Programmer VF display is inoperative, refer to Air Delivery and Temperature Controls: Automatic for electrical schematics and diagnosis. Heating and Air Conditioning
6. If the Instrument Panel Cluster (IPC) VF display is inoperative, refer to Instrument Cluster for electrical schematics and diagnosis. Instrument Panel, Gauges and Warning Indicators
7. If the Head-Up Display (HUD) VF display is inoperative, refer to Head Up Display for electrical schematics and diagnosis. Heads Up Display Unit
8. Before component replacement, check for poor connections at related component and in-line harness connector terminal connections.
^ Check for a broken (or partially broken) wire inside of the insulation which could cause system malfunction but prove "GOOD" in a continuity/voltage check with a system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be checked by monitoring for a voltage drop with the system operational (under load) (refer to General Troubleshooting Procedures).
^ Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems (refer to General Troubleshooting Procedures). Diagnostic Aids