Headlamp: Description and Operation

Headlamps
The headlamp switch lever is located on the left side of the steering column. A twist-type knob controls the operation of the parking lamps and headlamps. A solid tone will sound as a reminder if you open the drivers door with the key out of the ignition and the park lamps or the headlamps on.

When either the parking lamps or headlamps are activated, the following lamps also illuminate:
- The tail lamps
- The rear license plate lamps
- The instrument cluster assembly lamps

Low Beam System Operation
The headlamps may be turned on two different ways. First, when the headlamp switch is turned to the ON position, the headlamps will illuminate. Voltage is applied continuously to the headlamp relay low pin 1 through the 60-amp lighting fuse and to headlamps through the 20-amp LH headlamp and 20-amp RH headlamp fuses. The coil is energized when the headlamp switch is switched to the ON position. When the coil is energized the relay provides a ground to low side of the headlamps which then illuminates the low beam headlamps. The second way the headlamps may be turned on is by switching the headlamp switch to the AUTO position. The body control module (BCM) will Illuminate the low beam headlamps when the light sensor detects the appropriate amount of light to turn ON the lamps.

High Beam System Operation
The high-beam headlamp operation is controlled using the turn signal switch lever on the steering column. In order to change headlamp operation from low-beam to high-beam, pull the headlamp dimmer switch until the detent is felt and release.


Flash-to-Pass System Operation
The Flash-to-Pass feature allows the driver to signal the driver of another vehicle his intention to pass. This is achieved by pulling the lever toward the driver, which will cause the high beam operation to illuminate until the lever is released. The operation of the headlamps with the turn signal switch in flash-to-pass mode is the same as the operation of the switch in the high beam mode except the lamps will turn off when the switch is released.

Automatic Lamp Control (ALC)
The automatic lamp control (ALC) includes Automatic Lamps ON, Automatic Lamps OFF and Approach Illumination features.

The automatic lamp control function only operates when the Auto Headlamp Control switch is in the AUTO position.

The automatic lamp control function includes the following features:
- Automatic lights ON, which is controlled by a light sensor.
- Automatic lights OFF, which is controlled by the ignition OFF/door open conditions.
- Approach illumination at night, which is activated by the remote coded key.
- When the switch is put in Park and pulled out, the fog lamps are activated.


Automatic Lights ON
This feature switches the headlamps and park lamps ON and OFF automatically based on the outside light level. The auto headlamp control switch must be in the AUTO position and the ignition switched ON to enable this feature. The lamps operate as per normal in other switch positions. A light sensor, located in the dashboard between the demist ducts, monitors the amount of light in front of the vehicle. The body control module (BCM) monitors the output of this sensor via BCM connector 2 terminal 2 and determines when the light level is low enough to turn the lamps on. The Automatic Lamps OFF feature works as per normal when Automatic Lamp ON is enabled.


Automatic Lights OFF
This feature switches the headlamps and park lamps OFF automatically. The BCM must sense the following sequence of events before the lamps are switched OFF automatically: A vehicle road-speed of less than 10 km/h (6 mph) without a sudden loss of speed, ignition being switched OFF with the vehicle travelling above 10 km/h (6 mph). The ignition has been switched from ON to OFF and remains OFF. The headlamp switch has not been turned ON after the ignition switch was turned OFF. The driver door has been opened. When the ignition is switched back ON, the lamps turn ON again based on the mode of headlamp operation and the position selected on the automatic headlamp control switch. Turning the switch to OFF deactivates the Automatic Lamps OFF feature. In the event of a system failure, the BCM default status of the lamp control output is ON when the ignition is ON. This gives direct control of the lamps to the automatic headlamp control switch.

Approach Illumination
The approach illumination feature in the BCM turns ON the low beam headlamps and park lamps for 30 seconds when the doors are unlocked with the remote coded key. This provides additional personal security when approaching the vehicle at night. The lights will automatically turn OFF if the vehicle is locked again with the remote coded key within 30 seconds of the approach illumination being activated. When the approach feature is initially activated, subsequent operation of the remote coded key unlock button will reactivate the lights to remain ON for an additional 30 seconds. The approach illumination feature only operates during dark conditions. To enable this to happen, the BCM monitors the output of the light sensor and determines when the light levels are low enough to enable the approach illumination feature to be activated. The headlamps resume normal operation when the ignition is switched ON.