Troubleshooting Hints

PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS
1. Always suspect an open lamp filament before proceeding with diagnostics.
2. If a Headlamp Bulb has been found damaged, check excessive moisture inside Headlamp. Excessive moisture can damage lamps.
3. Make sure lamp connections are free from corrosion.
4. Make sure Headlamps and Park Lamps operate normally when using the Headlamp Switch before proceeding with Daytime Running Lamp (DRL) diagnosis.
5. Make sure the Brake Warning System is functioning properly. DRL will not turn "ON" if Park Brake is "ON."
6. Check Fusible Link Z for open.
7. Check Turn B-U Fuse 2, Gages Fuse 9 and TAIL LTS Fuse 10 for open. If fuse(s) are open, replace fuse(s). If fuse(s) open again, check for short to ground in the suspected circuit(s).
8. On Pontiac Models if Headlamp door(s) do not open and Headlamps do not illuminate, repair Headlamp door(s) failure first. Refer to "Headlamp Doors". Headlamp
^ 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 he 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 (refer to "Troubleshooting Procedures"). Diagnostic Aids
^ Refer to System Diagnosis.