Troubleshooting Hints

TRY THE FOLLOWING CHECKS BEFORE DOING SYSTEM DIAGNOSIS.
^ (With T61 or T82) If headlamps operate properly from Head/Park Lamp Switch, but do not turn on automatically when equipped with Twilight Sentinel (T82), refer to Ambient Light Sensor. Ambient Light Sensor
1. If one Headlamp doesn't work, check bulb, connector, and wiring to bulb.
2. If HI Beams do not light, but HI Beam Indicator lights, check LT GRN (11) wiring (see schematic) for an open, and check suspect Headlamp Assembly Connector for proper terminal contact.
3. If Headlamps on one side are dim, check the ground on that side. Check suspect Headlamp Assembly Connector for proper terminal contact.
4. If Fog Lamp indicator does not turn off, replace Fog Lamp Switch.
5. If HI Beams light, but HI Beam Indicator does not, check bulb and LT GRN (11) and BLK (150) wiring for an open. Check Instrument Cluster Connector (see schematic) for proper terminal contract.
(6 - 8 Oldsmobile Only)
6. If Fog Lamp indicator does not turn off, replace Fog Lamp Switch.
7. If Fog lamps do not operate check RH Front Underhood Relay Center, Fog Lamps Fuse.
8. If Fog Lamps are on at all times, check PPL (34) wire for short to voltage. If wiring is OK, check that Fog Lamp Relay contacts are not stuck closed.
9. If Flash To Pass is inoperative, on Oldsmobile check RH Underhood Relay Center Fog Lamps Fuse, on Buick check RH Underhood Relay Center Flash To Pass Fuse.
10. Before Component replacement, check for poor connections at related component and in-line harness connector terminal connections.