Troubleshooting Hints - Interior Lights Dimming

PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS
1. Check that the park lights are operating properly. If not, refer to Exterior Lights. Testing and Inspection
2. If only the VF display for the instrument cluster is inoperative, refer to Instrument Cluster: Indicator or Instrument Cluster: Gauges. Instrument Panel, Gauges and Warning Indicators
3. If only the VF display for the radio is inoperative, check the IP fuse block RADIO Fuse 8D by visual inspection. If open, check for a short to ground in CKT 43 (YEL). If OK, check for an open in CKT 43 (YEL) between S203 and the radio.
4. If only the VF display for the heater and A/C programmer is inoperative, check the IP fuse block AUTO A/C/CRUISE Fuse 5A by visual inspection. If open, check for a short ground in CKT 1141 (BRN). Refer to HVAC-Air Delivery and Temperature Controls: Automatic for schematic. Heating and Air Conditioning
5. For Buick and Oldsmobile, if only the VF display for the heater and A/C programmer does not dim, check for an open or short ground in CKT 724 (PPL/WHT).
6. If only the VF display for the head-up display (HUD) is inoperative, refer to Head-Up Display. Heads Up Display Unit
7. Check the IP fuse block INTERIOR LPS Fuse 8B by visual inspection. If open, check for a short ground in CKT 32 (YEL).
8. For Buick, check the P fuse block MISC/RDO/CLSTR Fuse 9C by visual inspection. If open, check for a short ground in CKT 40 (ORN).
9. Check that grounds G101, G105, G201, and G202.
10. If only one light does not operate or dim, check bulb, socket and related wiring.
11. For Buick, if all incandescent lamps light, but do not dim, replace the remote dimmer module.
12. For Oldsmobile, if all incandescent lamps light, but do not dim, replace the panel dimmer module.
13. For Pontiac, if all incandescent lamps light, but do not dim, replace the headlamp switch.
14. Before component replacement, check for poor connections at related component and in-line harness connector terminal connections.
15. Check for broken (or partially broken) wire inside of the insulation which could cause a 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).
16. Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems.