Troubleshooting Hints

PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS
1. Check Underhood Bussed Electrical Center (BEC) SBM/LCM Fuse 2, HDLP Fuse 40, LP PK Fuse 24, HDHIBML Fuse 16, HDHIBMR Fuse 14, HDLOBML Fuse 19, and HDLOBMR Fuse 18 by visual Inspection.
2. If one headlamp doesn't operate, check bulb, socket and related wiring (see schematic).
3. If headlamps on one side are dim, check ground on, that side.
4. Check that grounds G105, G106, and G202 are clean and tight.
5. Before component replacement, check that system connections are clean and tight.
^ 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