Adaptive headlights failure in BMW

Water or condensation within the headlight is the most common cause for adaptive headlights failure BMW. Because the moisture can damage the adaptive headlight module. If there is no water or condensation inside the headlight, then the adaptive headlights could be failing because of a damaged or worn out part in the headlight. The second thing is failure of height sensor in vehicle can also cause to store this warning indicator in the system. As in BMW headlights range change up and down as per the signal from ride height sensor. Due to which if there will be any failure occurs at ride height sensor than also this warning indicator will illuminate on cluster. Ride height sensor is directly connected with the headlight unit to send signal of about the height of vehicle.

In latest model of BMW there is only one headlight control unit to control the entire operation of headlight. But in old model like E70, E90 and all they have headlight control unit also known as cassettes in headlight to control headlights.

Causes of Adaptive headlights failure in BMW :

Failure of headlight from inside.

Faulty ride height sensor.

Damage wiring harness of ride height sensor.

Damage wiring harness of headlight.

Faulty headlight control unit.

Headlight calibration require.

Symptoms of Adaptive headlights failure in BMW :

Warning indicator will illuminate on cluster and center display.

Fault code will store in control module.

Headlight will not work properly.

Low or high beam may stuck at the same position.

Solution of Adaptive headlights failure in BMW :

When found warning indicator on cluster or center display. First thing is to do that check headlight behavior that what kind of problem is occurring at headlight. There would be some misbehavior at headlight due to which this warning indicator in illuminating on cluster meter. Like headlight high or low beam is stuck at same position there is no changes, day light will not working, indicator light will not work.

This problem could be happen due to failure of ride height sensor. Failure ride height sensor could be occur due to installing it in wrong position, like when mechanic do suspension work they need to remove ride height sensor. While reinstalling ride height sensor it might be possible that sensor position would change. When ride height sensor position will change than it will send wrong signal to headlight control unit of about height of vehicle. Due to which headlight will do little bit misbehavior due to receiving wrong signal from height sensor.

 Either wiring harness of ride height sensor is damage from somewhere. Check wiring harness of the ride height sensor if found any damage wire than repair it. The most of the time this problem happen due to fault at rear ride height sensor. Check properly position of rear ride height sensor and wiring harness of the sensor.

If ride height sensor is properly installed and wiring harness is also not damage from anywhere. Than go to check headlight control unit which is located at the back side of headlight. When this warning light will illuminate on cluster meter than there would be some fault code will also store which will indicate that which side of headlight is having fault in it.

 Now start working according to that fault code, if fault code indicate problem at right side headlight than swap left side headlight to right side headlight. If fault code change ( first it was showing problem in right side but after swapping headlight fault change and now it showing problem in left side). Than this indicate that there is a problem inside headlight.

When fault code does not change after swapping headlight from left to right than it is clear that there is no problem at headlight. Now you need to check wiring harness of the headlight and voltage at the connector of headlight. Remove connector of headlight and check voltage properly according to manufacturer. If there is some power supply, ground and signal is not present. Than this could be happen due to damage wiring harness of the headlight. Find that damage wiring harness and repair it so that problem can be solve.

Solution :

Install proper ride height sensor.

Replace faulty headlight unit.

Replace faulty headlight.

Repair damage wiring harness of the sensor.

Calibrate headlight system.

How to check failure of headlight:

To check failure of headlight you need to remove both the headlight outside. Check connector of headlight if they are same, means there check wiring harness connector pins if they are equally aligned than you can swap headlight from left to right to check if headlight have internal failure inside it.

But if the connector pin is not aligned equally than do not swap headlight to each other. Because doing this can leak to short circuit at the connector or inside headlight. In this situation try to swap left side headlight with old one headlight from other vehicle. Now if there is no warning indicator illuminate on the cluster than it mean that headlight is faulty.

How to check failure of headlight control unit:

To check failure of headlight control unit remove headlight control units from headlights. Check there connector pin if there connector pins are equally align than swap headlight control unit from each other. If fault code change from left to right side than it means than headlight control unit is faulty.

In case if there connector pins are not equally align than do not try to swap headlight control unit. As there is a high chance of short circuit at headlight control unit and wiring harness. In this situation try to swap headlight control unit with use control unit or from other vehicle headlight control unit. Now if there is no warning indicator is illuminating on cluster meter than it means that headlight control unit faulty. Replace that faulty control unit with new headlight control unit so that problem can be solve.

How to check failure of ride height control sensor:

Ride height control sensor is use to monitor the height of vehicle from each side of vehicle. Ride height control sensor send signal to ride height control module, ICM control module, headlight control unit in the form of voltage with the help of CAN signal wire. When there is some problem occurs at ride height control sensor than they send wrong signal to control modules. Due to which control module store fault code of faulty signal from that sensor. Sometime while working on suspension mechanic need to remove ride sensor. But at the time of installing ride height sensor they install that sensor in wrong position. Because of which control module will store fault code in the system.

 Checking of failure of ride height sensor could not be easy. You can read the data of sensor with the help of scan tool or manually also. Remove arms of sensor from its ball joint, if you will manually take sensor arms towards downside than reading of the sensor will increase. If you pull the arm of sensor towards of upside than reading of the sensor could show decreasing. If this phenomenon is happening than it means that ride height sensor is working very fine.  But if it does not than replace that faulty sensor with new working sensor.

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