Xenon headlight issue

[Bgearhart]

I am new to BMW. I bought a 2007 328 xi for my kid. Not sure what the code is, if it is a E90 or what. The headlights were not working when we bought it. I replaced the xenon bulbs and still nothing. So I have now replaced both of the ballast. There are no aftermarket LEDs in the vehicle either. When the car is in the acc position the lights come on fine. Once you start the vehicle and turn the lights on they flicker very fast like a police car. I am not very mechanically or electrically inclined. Please help if you may know how to or have had a similar problem. Thanks

[MarcoZandrini]

The car is an E90. How old is the battery? Are you having any other electrical or electronic issues? Do you have a digital volt/ohm meter?

[White94RX]

Sounds like you might need to take it to a professional.

[Bgearhart]

The battery looks fairly new. There are no other electronically issues with the vehicle. Yes I do have a meter.

[jclausen]

Under neath the each headlight is the module which lights the bulbs off, are prone to water damage, especially when the covers are missing that allow bulb access. But both headlights having bad modules not so often, but it could happen you need to check for faults

[Bgearhart]

But they work fine when the car is not running. It is only when the car is running do they flicker.

[MarcoZandrini]

Do you have a digital volt/ohm meter? Check the voltage under both circumstances to see if there’s a difference. You may have to find a place that can see the voltage on an oscilloscope. The alternator may be the root cause of the lighting issue.

Are you seeing any other electrical/electronic issues? These cars are rolling computers and whacky voltages cause whacky issues.

[Bgearhart]

I will have the volts checked. There are no other issues with the vehicle. Thanks

[MauiM3Mania]

Moved from BMW General Discussion sub-forum.

[Leishen]

Assuming the headlamp has been properly installed /mounted and this is the only one flickering (if more than one, check your regulator) then that lamp needs a constant load resistor added or the device that suppresses this is missing (either the mfgr or installer mishap).


This especially true if the high beam lamps work fine but the dimmer or dim/low beams (regular) setting is faulty.


Also, make sure that the neutral or ground wire and hot wire are securely mounted (snug).
More information about LED headlight bulb, can check below website
http://www.leishenled.com/W/DynamicNews.html