Autolamps

Autolamps

Overview

The autolamp system consists of:

- Light sensor

- Headlamp switch (integrated into the FLM (Front Lighting Control Module))

- BCM (Body Control Module)

The autolamp system provides light sensitive automatic on/off control of the exterior lamps. The autolamp system keeps the exterior lamps on for a preselected period of time after the ignition is turned off (20 seconds is the factory default setting). The preselected time lapse is adjustable up to approximately 3 minutes. To change the autolamps time delay, REFER to Autolamps Time Delay Adjustment Autolamps Time Delay Adjustment.

System Operation

System Diagram





Network Message Chart

BCM (Body Control Module) Network Input Messages






Autolamps

The BCM (Body Control Module) monitors the light sensor with a voltage signal. The light sensor input to the BCM (Body Control Module) varies with the ambient light conditions.

When the BCM (Body Control Module) receives a headlamp switch status message from the FLM (Front Lighting Control Module) indicating a request for the autolamps, the BCM (Body Control Module) monitors the light sensor for the ambient light condition. If the BCM (Body Control Module) determines the ambient light level is dark, the BCM (Body Control Module) supplies voltage to the exterior lamps.

If the vehicle enters a dark/lighted area (such as when entering/exiting a non-lighted tunnel during the daytime), the transition from light to dark (or dark to light) needs to last 15 seconds before the BCM (Body Control Module) turns the exterior lamps on or off. This strategy prevents the exterior lamps from unnecessarily flashing on and off.

The BCM (Body Control Module) reacts quicker under extreme light conditions. If the BCM (Body Control Module) has detected a very dark condition, the exterior lamps are turned on after 1.5 seconds. If the BCM (Body Control Module) has detected a very high ambient light level, the exterior lamps are turned off after 4 seconds.

Headlamps On With Wipers On Function

When the headlamp switch is in the AUTOLAMPS ON position, the exterior lamps turn on when the front wipers are on for more than 3 seconds (if wipers are turned on manually) or 30 seconds (if the wipers are on from the rain sensing wiper system). This feature does not activate the exterior lamps during a mist wipe or while the wipers are on to clear washer fluid during a wash condition.

The exterior lamps turn off when the ignition is changed to OFF or ACCESSORY, the headlamp switch is placed in the OFF position, or the front wipers are off for more than 30 seconds (60 seconds if on from the rain sensing wiper system). The exception to this is when the exterior lights are on because of darkness determined by the light sensor.

Component Description

Light Sensor

The BCM (Body Control Module) sends a voltage signal to the light sensor. The light sensor provides resistance between the voltage signal and ground. The resistance varies depending on the amount of ambient light detected by the light sensor. The brighter the ambient light, the lower the resistance. By varying the resistance, the BCM (Body Control Module) can determine the amount of ambient light.