Lighting and Horns: Description and Operation
The content of this article reflects the changes called out by TSB's 26-05-00 and 26-12-00.LAMP SYSTEMS
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 Control Module. The headlamp, dome, and the door ajar switches provide signals to the Body Control Module. The Body Control Module 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.
AUTOMATIC HEADLAMP SYSTEM
The Automatic Headlamp system turns the instrumentation and exterior illumination lamps ON when the ambient light levels are low and OFF when light levels are high.
Automatic headlamps are controlled by the Body Control Module (BCM). With the headlamp switch in the AUTO position, the BCM will control the headlamp, parking, side marker, tail and instrumentation lamps based on ambient light levels. Ambient light levels are monitored by the BCM using the automatic temperature control system Sun load Sensor, located on the back of the Interior Electrochromic Mirror. Ambient light readings are averaged to limit cycling the lamps ON and OFF when passing through areas with varying light levels. The automatic headlamps will only function when the engine is running. When the headlamp switch is in the AUTO position (Automatic mode), the Headlamp Time Delay system will function when the ignition is switched OFF.
COURTESY LAMPS
The Body Control Module (BCM) illuminates the courtesy lamps whenever a door is opened. When the last door is closed, the BCM will turn the courtesy lamps off in about 30 seconds. If a door is left ajar, the courtesy lamps remain on for a maximum of 15 minutes when the ignition switch is OFF.
ELECTRONIC DAYTIME RUNNING LIGHT (DRL)
Junction Block Terminal Pins:
The Combination Flasher/DRL is a module providing turn signal, hazard warning, and daytime running light functions (for Canadian vehicles), and has been designed with internal relays to take advantage of low current switching requirements in the vehicle. It is plugged into the junction block at positions three and four, where all wiring associated with its operation is terminated. The junction block is adjacent to and left of the steering column of the vehicle.
On vehicles built for use in the United States, only position four is used. Vehicles built for use in Canada utilize both positions three and four.
To gain access to the device, remove the lower steering column cover and knee blocker.
The combination-flasher/DRL may be operated in its hazard warning mode either with or without the ignition circuit being active. However, in order to operate in the turn signal mode or the DRL mode, the ignition circuit must be completed to the module.
While the combination-flasher portion is idle, there is no current drawn through the module. The device does not become active in the turn signal or hazard warning modes until a signal ground circuit is supplied to either of the turn signal inputs or the hazard warning input. With the ignition OFF, there is no current drawn through the module.
While the ignition is ON, the front turn signal filaments are illuminated steadily thus providing the DRL function. The DRL function may be inhibited by applying a signal ground input from either the park brake circuit or the headlamp relay activation circuit.
HEADLAMPS ON WITH WINDSHIELD WIPERS
For vehicles equipped with the Automatic Headlamp System, the instrumentation and exterior illumination lamps will be turned ON when the headlamp switch is in the AUTO position and the windshield wipers have been in the intermittent, low or high mode of operation for more than ten seconds. When the windshield wipers are turned OFF the Body Control Module will determine if the instrumentation and exterior illumination lamps should remain ON base upon the current ambient light level.
HEADLAMP SYSTEM
The headlamp system is controlled completely by the Body Control Module (BCM). The BCM controls the Park lamps, Headlamps, and Front Fog Lamps using relays located in the Junction Block. Three wires are connected between the headlamp switch and the BCM. The first wire contains information regarding the position of the headlamp switch (Off, Automatic Headlamps, Automatic Headlamp switch fog, Park with Fog, Head, or Head with Fog Lamps). The second wire contains information regarding the position of the dimmer switch (Dome Lamp, Daytime Brightness, or Dimming Level). The third wire is a dedicated signal return (ground) wire.
The headlamp system will default to headlamps ON position when ignition switch is ON when an open or short circuit failure occurs on the headlamp switch input. The system will return to normal operation when the open or short is repaired. A fault will be reported by the BCM when a failure occurs on the dimmer or headlamp switch input.
The dimmer system Will default to Daytime Brightness when an open or a short occurs on the dimmer switch input.
The BCM will turn OFF the exterior lamps if they are left ON with the ignition switch OFF for more than ten minutes. This feature prevents the vehicle battery from being discharged when the vehicle lights have been left ON.
HEADLAMP TIME DELAY SYSTEM
The Headlamp Time Delay system is controlled by the Body Control Module (BCM) through the headlamp relay.
The headlamp time delay system is activated by turning the headlamps ON (high or low beam) while the engine is running, turning the ignition switch OFF, and then turning the headlamp switch OFF within 45 seconds. The system will not activate if more than 45 seconds elapse between ignition switch OFF and headlamp switch OFF. The BCM will allow the headlamps to remain ON for 90 seconds before they automatically turn OFF. Refer to the Owner's Manual for more information.
ILLUMINATED ENTRY
The Illuminated Entry System is available on vehicles equipped with the Remote Keyless Entry system. The Illuminated Entry System turns ON the courtesy lamps when the remote keyless entry system is activated.
The Remote Keyless Entry Module and the Body Control Module (BCM) are used to control the system. Courtesy lamps will turn on for 30 seconds (± 1 second).
The Illuminated Entry System also turns ON the courtesy lamps when a door is opened. The courtesy lamps will remain ON while the door is open, then "turn OFF" 30 seconds (± 1 second) after the last door is closed.
The Illuminated Entry System cannot be activated during the 30 second (± 1 second) period after the ignition switch is turned OFF except by using the RKE transmitter. If a door is opened and closed during this 30 second period, the system will function as previously described.
The courtesy lamps will turn OFF immediately, if the Remote Keyless Entry lock function is actuated with all doors closed.
SAFETY PRECAUTIONS
WARNING: EYE PROTECTION SHOULD BE USED WHEN SERVICING LASS COMPONENTS. PERSONAL INJURY CAN RESULT.
CAUTION:
- Do not touch the glass of halogen bulbs with fingers or other possibly oily surface, reduced bulb life will result.
- Do not use bulbs with higher candle power than indicated in the Bulb Application table. Damage to lamp and/or Daytime Running Lamp Module can result.
- Do not use fuses, circuit breakers or relays having greater amperage value than indicated on the fuse panel or in the Owner's Manual.
When it is necessary to remove components to service another, it should not be necessary to apply excessive force or bend a component to remove it. Before damaging a trim component, verify hidden fasteners or captured edges are not holding the component in place.