Having a car doesn't only mean having to maintain the engine components, braking system, suspension system, exhaust system, etc. The headlight assembly is also very important because they provide visibility especially when driving at night. And according to the United States Traffic Department, 25 percent of all road accidents occur at night, posing a great risk for any automobile driver. It helps to familiarize yourself with, and know the reasons behind, the common problems you may encounter with your BMW 528i headlight assembly. This knowledge will help you lower your risk of meeting an accident.
Condensation inside the headlight assembly occurs with the intrusion of moisture. This happens when the seals in the bulb holes are not working properly or are completely worn out. Another possible cause is having cracks anywhere in the assembly. Both causes allow moisture to come in and fog up the lenses, thereby reducing nighttime visibility.
Over time, the sun's harmful UV rays can cause a buildup of loose oxygen electrons that are attracted to the surface of the lenses. You will not be able to prevent this entirely, since the headlamps are constantly always exposed to all kinds of environments and weather conditions. What you can do is to remove the oxidation from time to time for it not to cause you poor visibility when driving at night.
Besides the lenses, the contacts that join the headlight to the wiring harness can also become oxidized. And if you live near the ocean, there is even a higher probability of experiencing this.
There is big trouble if your BMW 528i headlight assembly doesn't produce even a flicker of light. If you experience this, you may have busted HID bulbs. Although they usually have an average useful life of 2,700 hours, age can come in and take its toll on the bulbs. Other reasons that cause busted bulbs include having a cracked or damaged lens that allows moisture to seep in and handling the bulb with bare hands. The oil from your fingerprints will eventually shatter the bulb.
BMW's HID bulbs rely on ballasts, also called Xenon Control Units, to turn on. A common cause of ballast failure is having worn out seals that allow moisture to damage it. Another reason for this is having damaged wires between the ballast and the HID bulb, resulting in insufficient current.