Chevrolet Equinox Service Manual: Exterior Lighting Systems Description and Operation Lighting Exterior Lighting

Exterior Lamps

The exterior lighting system consist of the followinglamps:

Automatic Headlamp LevelingHeadlampsAdaptive Forward LightingDaytime Running Lamps (DRL)Front Fog LampsRear Fog LampsPark, Tail, License and Marker LampsTurn Signal LampsHazard Warning LampsRepeater LampsStop LampsBackup LampsPosition LampsLow Beam Headlamps (Standard) RPO TT4

The headlamps consist of 2 interchangeable single filamentbulbs or 2 high intensity discharge (HID) arc tubes and ballast oneach side of the vehicle which provide high and low beams. Thelower bulb in the headlamp is the high beam and the upper bulb isthe low beam.

The headlamps may be turned ON in 3 different ways:

When the headlamp switch is placed in the ON position, fornormal operationWhen the headlamp switch is placed in the AUTOMATIC LIGHTposition, for automatic lamp controlWhen the headlamp switch is placed in the AUTOMATIC LIGHTposition, with the windshield wipers ON in daylight conditions,after a 6-seconds delay

The body control module (BCM) controls the headlamps based onthe inputs explained above. When a low beam request is received,the BCM supplies an B+ through the headlamp low beam relay for theleft headlamp and through daytime running lamp relay - right forthe right headlamp. This then applies B+ to the low beam headlamps,illuminating the low beam headlamps. When a high beam request isreceived, the BCM grounds the headlamp high beam relay controlcircuit. This energizes the coil in the headlamp high beam relay,causing the relay switch to close. This then applies B+ to bothhigh beam headlamps through the left high beam and right high beamfuses, illuminating the high beam headlamps.

Adaptive Forward Lighting

The adaptive forward lighting consist of the followingcomponents:

Headlamp control moduleHeadlamp actuator – leftHeadlamp actuator – right

Dynamic Curve Light

Bend lighting is a function depending on the following signalinput values:

Steering angleVehicle speedYaw Rate

The appropriate swivel angle is calculated based on vehiclespeed and the steering angle value.

Cornering Light

The cornering lamp is activated automatically at vehiclespeeds below 40-km/h (25-MPH) when thedirection indicator is switched ON and/or when the steering angleis changed from the straight-ahead position towards the side thevehicle is going to turn and passes a programmable angle threshold.The cornering lamp is deactivated automatically when the directionindicator is switched OFF and/or the steering angle has returned inthe straight-ahead position. The cornering lamps are deactivated atvehicle speeds above 40-km/h (25-MPH). Ifreverse gear is active, the cornering lamps go into park function.Both lamps will be switched on. They will switch off20-seconds after leaving reverse gear or if the vehiclespeed exceeds 7-km/h (4-MPH). The corneringlamps also provide a protection against overheating. When havingbeen continuously switched on for 2-minutes, adaptiveforward lighting will deactivate the lamps for 2-minutesto enable cooling down.

Town Light

Town Light is activated while the vehicle speed is below55-km/h (34-MPH) as well as the light sensordetects street lights and the town road category is detected. Thelight distribution is reduced to an area near the car due to lowspeeds.

Motorway Light

If vehicle speed is above 100-km/h(62-MPH) for at least 20-seconds (or onceabove 126-km/h (78-MPH) and the correspondingroad category is identified, the headlamps will be switched to amotorway light distribution. During motorway light the light outputof the HID bulb is increased to 38-W by electrical powermanagement. This improves the visibility range at the far end ofthe road.

Country Light

Country light replaces the current low beam and will becontrolled based on programmable vehicle thresholds as well ascorresponding road detection. The vehicle speed has to be between55-km/h (34-MPH) and 100-km/h(62-MPH). Country light is the default lightdistribution at 35-W. Light distribution is reduced onthe left side to prevent oncoming traffic from beingdazzled.

Tourist Mode

The tourist mode functionality switches the adaptive forwardlighting headlamps into a non dazzling mode, if the trafficregulation moves from left hand traffic to right hand traffic andvice versa. The functionality is switched on/off with the samestalk/switch combination. The “flash to pass”stalk needs to be activated while ignition is switched on (SystemPower Mode = RUN). The “flash to pass” stalkremains activated until the warning indicator within the instrumentpanel cluster starts flashing (4-seconds) and anacoustic indication is sent. The activation period takes about3-seconds. An activation flag must be set within theadaptive forward lighting ECM and stored in non-volatile memory.Each time the ignition is switched on and the tourist mode isactive, the warning indicator is flashing about4-seconds. The tourist mode is deactivated with the sameprocedure described above. The function is switched OFF, if anacoustic signal is sent (Warning indicator remainsinactive).

Adverse Weather Light

Adverse weather light will be switched on while the vehiclespeed is below 100-km/h (62-MPH) and thewindscreen wipers are activated. The HID bulbs will be powered withdifferent values:

Left: 32-WRight: 38-W

The main advantage is that reflections on the wet floor arereduced to a minimum. This is noticeable as well for oncomingtraffic as for the driver. In front of the car a less illuminatedarea is realized.

The following conditions must be met before the adaptiveforward lighting will operate:

Automatic Lamp Control

Automatic Light is switched ON as default. It can be switchedOFF by turning the light switch to OFF position. It will beswitched ON again by doing so again. Automatic Light is onlyavailable if a rain sensor or rain/light sensor module in installedin the car. The rain/light sensor module will send the actualambient light state (day/night) to the BCM. If Automatic Light isenabled, BCM will react on the message received from the rain/lightsensor module by switching ON/OFF low beams.

Flash to Pass (Standard) RPO TT4

When the low beam headlamps are on and the turnsignal/multifunction switch is momentarily placed in the flash topass position, ground is applied to the turn signal/multifunctionswitch. The turn signal/multifunction switch applies ground to theBCM through the flash to pass switch signal circuit. The BCM thenapplies ground to the high beam relay control circuit. Thisenergizes the high beam relay, closing the switch side contacts ofthe high beam relay, applying battery voltage to the left and righthigh beam fuses. Battery voltage is applied from the high beamfuses through the high beam voltage supply circuit to the high beamheadlamp assemblies. This causes the high beam headlamps toilluminate at full brightness momentarily or until the flash topass switch is released.

Flash to Pass (up level) RPO TT2/TT6

When the low beam headlamps are ON and the turnsignal/multifunction switch is momentarily placed in the flash topass position, ground is applied to the turn signal/multifunctionswitch. The turn signal/multifunction switch applies ground to theBCM through the flash to pass switch signal circuit. The BCM sendsa message to the headlamp control module to lift the shutter fromthe Xenon lamp. This causes the Xenon lamp to illuminate theheadlamp at full brightness momentarily or until the flash to passswitch is released.

Automatic Headlamp Leveling

The Automatic Headlamp Leveling Systems consist of thefollowing components:

Ballast module – leftBallast module – rightHeadlamp leveling actuator – leftHeadlamp leveling actuator – rightHeadlamp control moduleHeadlamp leveling sensor – frontHeadlamp leveling sensor – rear

The automatic headlamp leveling system automaticallymaintains the vertical alignment of the headlamps when the vehicleload and driving conditions change. The headlamp control modulereceives inputs from the front and rear headlamp leveling sensorsto determine vehicle pitch. The headlamp leveling sensors send anoutput to the headlamp control module as the vehicle suspensioncompresses and rebounds. The headlamp control module calculates thedifference in vehicle pitch and sends a command to the (HID)ballast. The ballast then drive the headlamp leveling actuators tothe position commanded by the headlamp control module. The headlampleveling system also monitors the performance of the HID bulb andballast. When the headlamp switch is placed in the ON position theheadlamps will go down, and then back up to the centerposition.

Daytime Running Lamps (DRL) without HID RPO TT4

The DRL bulbs are combined with the park lamps. One filamentis for the DRL and one for the park lamps. The DRL will operatewhen the following conditions are met:

Engine is running.Headlamp switch in AUTOMATIC LIGHT position.The high and low beam headlamps are OFF.

By turning the headlamp switch in the OFF position theautomatic light function and the DRL will be deactivated.

The ambient light sensor is used to monitor outside lightingconditions. The ambient light sensor provides a voltage signal thatwill vary between 0.2–4.9-V depending onoutside lighting conditions. The HVAC control module provides a lowreference ground and 5-V reference signals to theambient light sensor. The BCM monitors the ambient light sensorsignal circuit to determine if outside lighting conditions arecorrect for either DRL or low beam when the headlamp switch is inthe AUTOMATIC LIGHT position. In daylight conditions, the BCM willcommand the DRL ON by applying ground to the left and right DRLrelays via separate left and right DRL relay control circuits. Whenthe BCM applies ground to the relay control circuits, the left andright DRL relay coils energize causing both relay switch contactsto close. With the left and right DRL relay switch contacts closed,battery voltage flows to the left and right DRL lamps. Any functionor condition that turns on the headlamps will cancel DRLoperation.

Daytime Running Lamps (DRL) with HID RPO TT2/TT6

The DRL are LEDs which are continuously illuminatedwhen:

Ignition is switched ON.Engine is running.High and low beam headlamps are ON or OFF.Headlamp switch is in PARKING LIGHT, AUTOMATIC LIGHT or LOWBEAM position.

By turning the headlamp switch in the OFF position theautomatic light function and the DRL will be deactivated.

The ambient light sensor is used to monitor outside lightingconditions. The ambient light sensor provides a voltage signal thatwill vary between 0.2–4.9-V depending onoutside lighting conditions. The HVAC control module provides a lowreference ground and 5-V reference to the ambient lightsensor. The BCM monitors the ambient light sensor signal circuit todetermine if outside lighting conditions are correct for only DRLor DRL and low beam when the headlamp switch is in the AUTOMATICLIGHT position. In daylight conditions the BCM will command the DRLON.

Front Fog Lamps

The front fog lamp relay is supplied with battery voltage atall times. The front fog lamp switch signal circuit is groundedmomentarily by pressing the front fog lamp switch. The body controlmodule (BCM) energizes the front fog lamp relay by applying groundto the front fog lamp relay control circuit. When the front foglamp relay is energized, the relay switch contacts close andbattery voltage is applied through the front fog lamp fuse to thefront fog lamp supply voltage circuit which illuminates the frontfog lamps.

Rear Fog Lamps

When the rear fog lamp switch is placed in the ON position,battery voltage is applied from the BCM to the rear fog lamps.Ground for the rear fog lamps is applied at all times.

The BCM will send a message via GMLAN serial data to theinstrument panel cluster to enable the rear fog lampindicator.

Park, Tail, License and Marker Lamps

The park lamps, tail lamps/LEDs and number plate lights areturned ON when the headlamp switch is placed in the Parking lightsor Low beam position or anytime the headlights are requested. Whenthe BCM receives a request from the headlamp switch to turn ON thepark lamps the BCM a sends out a PWM signal, which illuminates thepark lamps, tail lamps and number plate lights.

Turn Signal Lamps

Ground is applied at all times to the turnsignal/multifunction switch. The turn signal lamps may only beactivated with the ignition switch in the ON or START position.When the turn signal/multifunction switch is placed in either theTURN RIGHT or TURN LEFT position, ground is applied to the BCMthrough either the right turn or left turn signal switch signalcircuit. The BCM then applies a pulsating voltage to the front andrear turn signal lamps through there respective voltage supplycircuits. When a turn signal request is received by the BCM, aserial data message is sent to the instrument cluster requestingthe respective turn signal indicator be pulsed ON and OFF.

Repeater Lamps

The repeater lamps are located in the front fender. Therepeater lamps are used as additional turn signal lamps, andoperate as described in the Turn Signal/Hazard Flasher Lampsdescription.

Hazard Flasher Lamps

The hazard flashers may be activated in any power mode. Thehazard switch signal circuit is momentarily grounded when thehazard switch is pressed. The BCM supplies battery voltage to allturn signal lamps in an ON and OFF duty cycle. When the hazardswitch is activated, the BCM sends a serial data message to theinstrument cluster requesting both turn signal indicators to becycled ON and OFF.

Stop Lamps

The brake pedal position (BPP) sensor is used to sense theaction of the driver application of the brake pedal. The BPP sensorprovides an analog voltage signal that will increase as the brakepedal is applied. The BCM provides a low reference signal and a5-V reference voltage to the BPP sensor. When thevariable signal reaches a voltage threshold indicating the brakeshave been applied, the BCM will apply battery voltage to the stoplamp control circuit and center high mounted stop lamp controlcircuit . When the control circuit is energized the stop lamps areilluminated.

Backup Lamps

When the transmission is placed in the reverse position, theengine control module (ECM) sends a serial data message to the BCM.The message indicates that the gear selector is in the reverseposition. The BCM applies battery voltage to the backup lamps. Thebackup lamps are permanently grounded. Once the driver moves thegear selector out of the reverse position, a message is sent by theECM via serial data requesting the BCM to remove battery voltagefrom the backup lamp control circuit.

Battery Run Down Protection/Inadvertent Power

To provide battery run down protection, the exterior lampswill be deactivated automatically under certain conditions. The BCMmonitors the state of the headlamp switch. If the park or headlampswitch is ON when the ignition switch is placed in either the CRANKor RUN position and then placed in the OFF position, the BCMinitiates a 10-minute timer. At the end of the10-minutes, the BCM will turn OFF the control poweroutput to the park and headlamp relay coils, deactivating theexterior lamps. This feature will be cancelled if any power modeother than OFF becomes active. The BCM will disable battery rundown protection if any of the following conditions exist. The parkor headlamp switch is placed in the ON to OFF position, and back tothe ON position during battery run down protection. The BCMdetermined that the park or headlamp switch was not active when theignition was turned OFF.