wvien

Headlights have been flickering on and off intermittently for the past month. Car has factory bi-xenons with Osram Xenarc bulbs.
Passenger side started flickering, sometimes turns off for a few seconds and turns back on. Some days it won't flicker at all. Happens when driving or idling.
Swapped the bulbs, and the driver side started doing the same so I got new bulbs. Everything was good for a few days and then the driver side started to flicker again. Swapped bulbs around again and the flickering followed to the passenger side.

Wondering if it has anything to do with the alternator or battery. Car was bought used from Land Rover, battery was dead and they replaced it with a Land Rover battery, not AGM. Battery died 6 months ago when I left my key in the ignition overnight. Boosted it and haven't had problems since.
Looking at the vehicle data display, the UB battery voltage is 11.9v before starting and goes to 14.2v shortly after starting. Voltage drops to 13.4 when accelerating and goes back to around 14.0. IB shows 15-20a after starting and slowly drops to 0.5-1 after 15 minutes of driving.

Is this just bad luck with bulbs or is there something else going on?

Demvang

I wonder how you were able to start with a battery below 12v. Have it fully charged and let's see how it goes.

samaritrey

What brand are your new bulbs? Bought from a reputable place?

wvien

I had the battery checked at Napa over the weekend and they said it was good. Hooked it up to a charger and left it overnight.

New bulbs are Morimoto XB from theretrofitsource. I swapped in the working Osram bulb to see if I still get flickers, haven't seen anything in 2 days. Will try swapping the bulb again to see if it comes back.

wvien

Last night I had one Morimoto bulb and one Osram bulb in. Both of these bulbs have not flickered before.
The new Morimoto bulb started flickering and then shut off for a few seconds before turning back on. Voltage was showing 13.4 at the time, car sitting in the garage idling.

97 GSX 97

Morimoto does usually make quality products, but for me at least it's been hit or miss with their bulbs. I've had bulbs last years, and others last just months.

The voltage does seem low though as well. I'd rule out the ballasts as it seems to be happening on both sides.

wvien

Did a little googling and it seems like the BMW guys are having headlight flickering problems as well. They think the problem is faulty grounding at the tail lights. I took a look at my passenger side tail light harness and the ground pin had some brown stuff on it. I just had the car in for the tail light recall but looking at the invoice they only replaced the lamp carrier and not the harness. I soldered on a ground wire to the plate on the carrier for now. Will have to take it back to the dealer to deal with the harness. Didn't notice anything on the passenger side. After I soldered the ground wire on I went for a short half hour drive and didn't see any flickering. Will see how it goes for the next few days.
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pozi240

Good stuff for tracking that down... and, before you posted this, I was going to say, "check the ground in the harness". I've seen more "weird ****" in cars due to old/bad grounds. I'm used to old VW's and Audi's, and over the years witnessed things I wouldn't have believed unless I saw it with my own eyes. Ever see a blown out tail light bulb in a MK II (85 - 92) VW Jetta/Golf due to coolant based corrosion?! I have, many times.... the cause... the coolant expansion tank had a flaky pressure relief valve, so, to release pressure after shutting the car off, the coolant would migrate up through the level sensor and into the wiring connector and eventually make its way through the entire wiring harness and end up at the ground connector at the tail lights. I **** you not... you could smell the coolant in the tail light harness.
Sorry for the slightly off topic story, but, I can easily see how an even slightly bad ground at your tail light could cause electrical abnormalities at the headlights.

wvien

So grounding the tail lights didn't solve the problem. Dropped by an alternator shop yesterday and they said voltage dropped to 12.7 a few times under load. Going to rip out the alternator tomorrow and replace.

pozi240

Ughh... that sucks, but, hey, you did some good troubleshooting and it sounds like the alternator shop found the root cause anyway..

wvien

Pulled the alternator, took it to 2 different shops to test and it tested ok. There was a very slight noise coming from the bearing. No one in the city had a voltage regulator in stock. Decided to put in a remanufactured alternator since it's already out of the car and the bearing noise. $400 later and it's still flickering.

Any other ideas?

mickey13

ever solve this problem?

wvien

Installed a new battery, still had the problem.

My sister has a newer 2012 C-Class, swapped her Philips bulbs into my car and the problem went away. I've been using her bulbs since.

superangrypenguin

Did her car now have this issue? Because if not...that's weird.

wvien

No issues with my bulbs in her car. Wish I could use my Osram CBI bulbs in mine.