When the sun goes down or the clouds come out, you rely on your BMW’s headlights to brighten your path and get you to your destination safely. Therefore, if your vehicle’s headlights malfunction, it can spell danger for you, your passengers, and your vehicle. Fortunately, most headlight malfunctions can be avoided, and those that cannot can easily be fixed by an experienced mechanic.
Causes of Automatic Headlight Failure
Over the years, BMW has developed high-tech headlights that are able to automatically shift their light beams to the left or right as needed. These are known as adaptive headlights, and they help you to see more of the road when you’re driving at night. Although these headlights tend to be safer than standard headlights, they are also more complex, which means that there are more ways for them to malfunction.
For example, one of the most common causes of headlight failure in BMWs is the introduction of water to the adaptive headlight module. The adaptive headlight module, which may also be referred to as the stepper motor controller, the adaptive headlight drive control unit lighting module, or the ALC is the component that controls when your BMW’s headlights turn. If you regularly drive through damp conditions such as heavy rain or flooding, water may enter the module, causing it to short out. As a result, this will prevent your BMW’s headlights from working properly.
Another common cause of adaptive headlight failure is problems with the headlight seal. Each of your BMW’s headlights has an access door to allow mechanics to work on the system, and each of those doors comes with a seal designed to keep water out. However, these seals may eventually crack and break, allowing moisture to seep into your vehicle’s headlights. Much like with the adaptive headlight module, this can cause electrical components within the system to short out, destroying the adaptive capabilities of your BMW’s headlights.
Finally, a third potential cause of adaptive headlight malfunctions is failure of the stepper motor. The stepper motor serves as the middleman between the adaptive headlight module and the headlights. When the module activates it, it rotates the beam projector, thus shifting the location of the headlights’ beams. Over time, the motor may burn out or the connection between the motor and the projector may fail, thus rendering the projector inert.
Signs of a Faulty Headlight
Regardless of whether the headlight seal fails or the stepper motor burns out, the end result will be the same: your BMW’s adaptive headlights will cease to work. If this happens, you should try to identify and solve the problem as soon as possible.
Fortunately, if the issue lies with your vehicle’s adaptive headlight module, the problem may diagnose itself. When water gets into the adaptive headlight module, the system usually triggers a sensor, causing an adaptive malfunction error message to pop up on your dashboard. If you notice this error message, you should bring your vehicle to a mechanic, as it almost certainly means that your vehicle’s headlights are malfunctioning.
In contrast, broken headlight seals and stepper motors are a little more difficult to diagnose. If you suspect that something is wrong with your vehicle’s headlights but haven’t received any error messages, you may want to manually inspect the system to see if your suspicions are correct. To do this, have a friend turn your BMW’s steering wheel while the vehicle is parked with its engine running. If the headlights don’t turn from side to side when they normally do, then there is a strong chance that a component of the adaptive headlight system has malfunctioned.
Your Repair Shop for Top-Notch BMW Repairs
Adaptive headlights are finicky components that can be quite difficult for the novice mechanic to fix. If your BMW’s headlights are malfunctioning, bring them to the experts at Woodinville Sports Cars.
Our certified technicians are proud to provide comprehensive repairs to customers in Bothell, Kenmore, Kirkland, Mill Creek, Redmond, Snohomish, and Woodinville, WA. We are extremely passionate about European vehicles and would love to help you keep yours running smoothly, so give us a call today or stop by the shop to find out what we can do for you.
* BMW M4 Headlight image credit goes to: Chiradech.