System Diagnosis - Exterior and Interior Lighting

Most lighting problems are caused by loose connectors, open or shorted wiring, burned-out bulbs, bad switches, inadequate grounds, or open fuses. Many of these problems are repaired by replacing a part that requires a special procedure (such as a lens and housing sealed together). For these repairs, follow the instructions normally included in the replacement parts package.

When removing a component that requires special sealing items (such as sealing washers), be sure to reinstall those items when replacing the component. Also, if any body sealing items (grommets, etc.) are disturbed, be sure to repair them so that the passenger compartment remains properly sealed.

Use the following general guidelines to diagnose a lighting system problem:
1. Verify the owner's complaint.
2. Attempt to operate other systems powered through the same fuse. If other systems powered through the same fuse are inoperative, replace the fuse.
3. Check for aftermarket (non-OEM) equipment. If add-on accessories are discovered, disconnect the system to make certain that its installation is not the cause of the problem.
4. Check all connectors and related wiring to the suspect electrical component. Check for poor mating of connector halves, or terminals not fully seated in the connector body (backed out). Also check for dirt or corrosion on the connector terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact.
5. Check related ground eyelets for a clean and tight connection.