Troubleshooting Hints - Interior Lights Dimming

PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS:
1. If only one lamp does not operate, check bulb, socket and related wiring (see schematic).
2. Check I/P Fuse Block PARK LP Fuse 6C, INTERIOR LIGHTING Fuse 8B, RADIO Fuse 8D, and BATT, CHIME, RDO, CLSTR Fuse 9C by visual inspection.
3. Check that grounds G105 (Oldsmobile and Buick), G201 (Oldsmobile and Buick), and G202 are clean and tight
4. 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).
^ Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems.