Headlights blink while driving

[Bdc101]

I have noticed over the past few weeks that I see both my headlights turn off briefly while I am driving. Today I noticed that the fog lights seemed to stay on while the headlights turned off. This happened 3-4 times in the first 5 minutes of my drive this morning, but after that I didn't see it happen again.

Here are some posts that I found on a search that seem similar:
https://xoutpost.com/bmw-sav-forums/...ker-issue.html
https://xoutpost.com/bmw-sav-forums/...lickering.html
I also just ordered a new alternator because my 3-year-old Bosch unit is making a squealing noise... but there have been no lights on the dash or other electrical issues.

Could low voltage or another alternator problem cause the lights to turn off momentarily? What else could cause this sort of problem? Note that my car is a 2003 3.0i with the xenon headlight option.

[80stech]

An overloaded circuit can cause the LCM to shut off like a circuit breaker and then re-set itself. I would think that that left and right circuits would be split but maybe not. There may be a short somewhere in the wiring or ballast or possibly even the bulb. Low voltage also means higher current so it's also possible (less likely) that a charging problem could be the culprit.

[Bdc101]

Do the ballasts shut off the light if they don't have sufficient voltage? I have never owned a car with xenons before so I'm unfamiliar with how to troubleshoot.

I will check to see if both headlights are on the same circuit, but if someone knows please chime in.

It's worth mentioning that the battery is only 12 months old as well (costco brand)

[80stech]

The ballasts work on voltage not current so yes, if a ballast is short on voltage it won't produce enough to light the Xenon.

[Bdc101]

Unfortunately it seems like newtis is totally closed, so I will have to go home and look through my Bentley manual to check the wiring diagrams and see how they are wired up.

[Bdc101]

I actually had a headlight error message appear on the dash when I was driving earlier today, and then checked codes with my foxwell:

"Code 79: Dipped Beam, Right Headlight Faulty"


But it definitely appears that both beams are shutting off simultaneously. It is hard to tell though. I had about a 15-min drive home last night and noticed the lights blinking on and off during the first 10 mins of my journey. But when I got home they were rock solid while I sat in my driveway for another 5 minutes. The code in the foxwell also went away without being reset.

Any more ideas here guys or things to try?

[80stech]

Open the hood and start checking for problems. These cars are supposedly bad for the wiring deteriorating in the headlite assembly so you might gave a look at that. Switching the bulbs and ballasts might give some clues as well.

[killcrap]

fairly common for the tail lamp ground circuits causing the xenon headlamps to flicker on and off

[X5chemist]

Out of curiosity. Does anyone sell a xenon light harness? When I replaced a second right side bulb, the wiring looked bad. I could see cracks in sheathing.

[miloh]

Originally Posted by X5chemist

Out of curiosity. Does anyone sell a xenon light harness? When I replaced a second right side bulb, the wiring looked bad. I could see cracks in sheathing.

I haven’t seen it anywhere. I have a second set of headlights I was working on modifying: I opened them and completely dismantled them (facelift, bixenon, adaptive) and when they’re completely apart you can take out the harness easily. M539 Restorations made a video recently (i think it’s the second from most recently uploaded video) where he does a restoration of the degraded wiring harness by heat shrink wrapping every wire so that the degraded wiring is sealed up and not replaced. If you really wanted to you could depin everything and do new wires but I’m going to proceed with heat shrink.

I’d also like to know if anyone sells the black housing separately. When I removed the lenses from my prospective mod set I tore off the U channel entirely on one. It’d be nice to have the black housing as a base to install into. I couldn’t find it anywhere.


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