Troubleshooting Hints

PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS
1. Check the engine compartment fuse/relay center MIRROR Fuse by visual inspection. If open, check for a short to ground in CKT 1740 (ORN).
2. Check the engine compartment fuse/relay center HDLPS Fuse by visual inspection. If open, check for a short to ground in CKT 340 (ORN).
3. Check the engine compartment fuse/relay center IGN 1 Fuse by visual inspection. If open, check for a short to ground in CKT 439 (PNK).
4. Check the engine compartment fuse/relay center DRL Fuse cavity B9 by visual inspection. If open, check for a short to ground in CKT 1640 (ORN).
5. For DeVille, check the engine compartment fuse/relay center DRL Fuse cavity A2 by visual inspection. If open, check for a short to ground in CKT 12 (TAN).
6. Check the engine compartment fuse/relay center L HDLP LO Fuse by visual inspection. If open, check for a short to ground in CKT 712 (YEL).
7. Check the engine compartment fuse/relay center R HDLP LO Fuse by visual inspection. If open, check for a short to ground in CKT 312 (TAN/WHT).
8. Check the engine compartment fuse/relay center L HDLP HI Fuse by visual inspection. If open, check for a short to ground in CKT 711 (DK GRN/WHT).
9. Check the engine compartment fuse/relay center R HDLP HI Fuse by visual inspection. If open, check for a short to ground in CKT 311 (LT GRN/BLK).
10. Check the rear compartment fuse block RADIO/PHONE Fuse by visual inspection. If open, check for a short to ground in CKT 40 (ORN/BLK).
11. If one headlight does not operate, check bulb, socket and related wiring (see schematic).
12. If headlights on one side are dim, check ground on that side.
13. Check that grounds G101 and G205 are clean and tight.
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.