Part 2
Automatic Lamp Control/Twilight SentinelPlace the turn signal/multifunction switch in the AUTO position for automatic lamp control. During automatic lamp control the headlamps will be off during daylight conditions but will turn on when the ambient light sensor detects low outside light level. The ambient light sensor is a light sensitive transistor that varies the voltage signal to the HVAC control module. The HVAC control module sends a signal to the body control module (BCM) via serial data commanding the BCM to apply ground to the headlamp low beam relay control circuit. This energizes the low beam relay, closing the switched side and applies battery voltage to the LEFT and RIGHT LOW BEAM fuses. Battery voltage is applied from the low beam fuses, through the low beam voltage supply circuits to low headlamp assemblies.
Flash to Pass (FTP)
When the low beam headlamps are on and the turn signal/multifunction switch is momentarily placed in the flash to pass (FTP) position, ground is applied from G200 to the turn signal/multifunction switch. The turn signal/multifunction switch applies ground to the body control module (BCM) through the FTP switch signal circuit. The BCM then applies ground to the high beam relay control circuit. This energizes the high beam relay, closing the switch side contacts of the high beam relay, applying battery voltage to the LEFT and RIGHT HIGH BEAM fuses. Battery voltage is applied from the High Beam fuses through the high beam voltage supply circuit to the high beam headlamp assemblies. This causes the high beam headlamps to illuminate at full brightness momentarily or until the flash to pass switch is released.
Automatic Headlamp Leveling - European Only
The Automatic Headlamp Leveling Systems consist of the following components:
* Ballast module - left
* Ballast module - right
* Headlamp leveling actuator - left
* Headlamp leveling actuator - right
* Headlamp control module
* Front headlamp leveling sensor - base
* Rear headlamp leveling sensor - base
* Left front strut position sensor - V-series
* Left rear strut position sensor - V-series
* Right front strut position sensor - V-series
* Right rear strut position sensor - V-series
Base
The automatic headlamp leveling system automatically maintains the vertical alignment of the headlamps when the vehicle load and driving conditions change. Each headlamp assembly contains a headlamp leveling motor that is controlled by the headlamp control module. The front and rear suspension position sensors provide the headlamp control module with suspension position information. Each sensor receives a 5-volt reference, signal, and low reference circuits from the headlamp control module. The sensors are connected to the control arms of the front and rear suspension. As the vehicle travels, the suspension compresses and rebounds moving the suspension position sensor arms. This causes the signal output of the sensor to change. The headlamp control module compares the information from both suspension position sensors and adjusts the headlamp leveling as needed. The headlamp control module is wired to each headlamp leveling motor with 4 directional motor control circuits.
V-Series
The automatic headlamp leveling system automatically maintains the vertical alignment of the headlamps when the vehicle load and driving conditions change. Each headlamp assembly contains a headlamp leveling motor that is controlled by the headlamp control module. The front and rear suspension position sensors provide the electronic suspension control (ESC) module with suspension position information. Each sensor receives a 5-volt reference, signal, and low reference circuits from the ESC. The sensors are connected to the control arms of the front and rear suspension. As the vehicle travels, the suspension compresses and rebounds moving the suspension position sensor arms. This causes the signal output of the sensor to change. The ESC sends the suspension position sensor values to the headlamp control module via serial data. The headlamp control module compares the information from both suspension position sensors and adjusts the headlamp leveling as needed. The headlamp control module is wired to each headlamp leveling motor with 4 directional motor control circuits. For more detailed information regarding ESC, refer to Electronic Suspension Control Description and Operation (Description and Operation).
Daytime Running Lamps (DRL) without HID
The daytime running lamps (DRL) will illuminate the right and left low beam headlamps continuously. The DRLs will operate when the following conditions are met:
1. The ignition is in the RUN or CRANK position
2. The shift lever is out of the PARK position for vehicles equipped with automatic transmissions or the parking brake is released for vehicles with manual transmissions.
3. The high and low beam headlamps are OFF.
The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 0.2 and 4.9 volts depending on outside lighting conditions. The HVAC control module provides a low reference ground and 5-volt reference to the ambient light sensor. The body control module (BCM) monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or automatic lamp control (ALC) when the headlamp switch is in the AUTO position. In daylight conditions the BCM will command the low beam headlamps ON. Any function or condition that turns on the headlamps will cancel DRL operation.
Daytime Running Lamps (DRL) with HID
The daytime running lamps (DRL) will illuminate continuously when the following conditions are met:
1. The ignition is in the RUN or CRANK position
2. The shift lever is out of the PARK position for vehicles equipped with automatic transmissions or the parking brake is released for vehicles with manual transmissions.
3. The high and low beam headlamps are OFF.
The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 0.2 and 4.9 volts depending on outside lighting conditions. The HVAC control module provides a low reference ground and 5-volt reference signals to the ambient light sensor. The body control module (BCM) monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or automatic lamp control (ALC) when the headlamp switch is in the AUTO position. In daylight conditions, the BCM will command the DRLs ON by applying ground to the left and right DRL relays via separate left and right DRL relay control circuits. When the BCM applies ground to the relay control circuits, the left and right DRL relay coils energize causing both relay switch contacts to close. With the left and right DRL relay switch contacts closed, battery voltage flows through the left and right DRL fuses to the left and right DRL lamps. Any function or condition that turns on the headlamps will cancel DRL operation.
Front Fog Lamps
The front fog lamp relay coil and switch terminals are supplied with battery voltage at all times. Ground is applied at all times at G200 to the front fog lamp switch inside of the turn signal/multifunction switch. When the front fog lamp switch is placed in the ON position, ground is applied through the front fog lamp switch signal circuit to the body control module (BCM). The body control module (BCM) energizes the front fog lamp relay coil by applying ground to the front fog lamp relay control circuit. When the front fog lamp relay is energized, the relay switch contacts close and battery voltage is applied through the FRONT FOG LAMP fuse to the front fog lamp supply voltage circuit which illuminates the front fog lamps. Ground for the front fog lamps is applied at all times at G101 for the left fog lamp and G102 for the right fog lamp.
The BCM will send a serial data message to the instrument panel cluster (IPC) to enable the front fog lamp indicator. The front fog lamps will deactivate when either the flash-to-pass or the high beam headlamps are turned ON.