Lighting and Horns: Description and Operation

GENERAL INFORMATION
DIAGNOSTIC PROCEDURES
NS vehicles use lighting on the interior and exterior of the vehicle for illuminating and indicating purposes. Lighting circuits are protected by fuses. Lighting circuits require an overload protected power source, on/off device, lamps and body ground to operate properly. Plastic lamps require a wire in the harness to supply body ground to the lamp socket. Replace sockets and bulbs that are corroded.

Some of the interior and exterior lighting functions are governed by the body controller. The headlamp, dome, and the door ajar switches provide signals to the body controller. The body controller in turn activates relay(s) in order to provide either a ground or feed line to the appropriate lamp(s).

Wire connectors can make intermittent contact or become corroded. Before coupling wire connectors, inspect the terminals inside the connector. Male terminals should not be bent or disengaged from the insulator. Female terminals should not be sprung open or disengaged from the insulator. Bent and sprung terminals can be repaired using needle nose pliers and pick tool. Corroded terminals appear chalky or green. Corroded terminals should be replaced to avoid recurrence of the problem symptoms.

Begin electrical system failure diagnosis by testing related fuses in the fuse block and power distribution center. Verify that bulbs are in good condition and test continuity of the circuit ground.