[marinmcgreevy]

Hi all,

My 12 year old E90 335i (2007) has had the driver’s side HID Xenon headlight go out. I cannot hear the ballast so I believe that is the culprit.

Questions for the group:
1. My car is 12yrs old with 130k mi. Should I replace both ballasts? How long do they last?
2. Should I replace the bulbs as well? How long do they last?
3. To get to the ballast and the bulb do you recommend removing the bumper, headlight, or wheel-well? I have reviewed DYI posts and there is no consensus.

Any and all advice will be greatly appreciated! I will post photos/info of the job.

Thanks!

Evan

[relative4]

To replace the bulb, you just open the access panel in the wheel well liner.
To replace the ballast, you have to jack up the front end, put it on jackstands, remove the front wheels, remove the belly pan, remove both wheel well liners, remove the bumper cover, and finally unmount the headlight and pull it partway out. Good times.

[MadJoe]

My E90 with Xenons, built in Nov. 2005 and with 180,000 miles on it, is still going with the OEM bulbs and ballasts. I actually bought both for both sides 3 or 4 years ago thinking I'd need them soon, but haven't yet.

That said, if the headlight comes back on for no obvious reason, or you are experiencing rougher-than-smooth idling, or starting causes the engine to jump around like there's a bad engine mount, or you've noticed a fall off of fuel mileage suddenly, or any other myriad electrical glitches (my dashboard lit up like a Christmas tree the other day telling my I had catastrophic brake failure that went away with a restart) check your starter ground cable.

I just replaced mine, and am noticing a huge difference in the car's idling, fuel mileage, and an assortment of electrical gremlins that had been nagging me going away.

You can see what I'm talking about here.

Joe

[BadContrakt]

Originally Posted by marinmcgreevy

Hi all,

My 12 year old E90 335i (2007) has had the driver’s side HID Xenon headlight go out. I cannot hear the ballast so I believe that is the culprit.

Questions for the group:
1. My car is 12yrs old with 130k mi. Should I replace both ballasts? How long do they last?
2. Should I replace the bulbs as well? How long do they last?
3. To get to the ballast and the bulb do you recommend removing the bumper, headlight, or wheel-well? I have reviewed DYI posts and there is no consensus.

Any and all advice will be greatly appreciated! I will post photos/info of the job.

Thanks!

Evan

I'm in the same boat. My passenger side bulb flips on, off, on, off, on, off, then on and DING the iDrive says headlamp malfunction or whatever TF it says.

Ballast is bad I'm pretty sure. So I've gotten a new one. If the driver side light works 100% and doesn't act up and is the same temperature (color) as the other headlamp, then why open that can of worms? I'm usually one to replace things symmetrically but, in this case, I'm replacing as needed. Now if we're talking BULBS I'm replacing those symmetrically for sure. But a ballast? Definitely only the one that's failing.

EDIT: If you want to know for sure if it's ballast or bulb, you can switch bulbs from left to right (much much easier than switching ballast from left to right) and if the problem moves, then it's bulb. If it doesn't move, remove and replace driver side ballast and move on. Leave bulbs and other ballast alone.

[marinmcgreevy]

Ended up replacing both sides ballast and bulbs. First replaced bulb on side that was out to confirm the ballast was out.

Some points:

1. The wire clip that holds the bulb in place is very difficult to reinstall with the headlight unit in the car.

2. Because of the clip I decided to remove the headlight assembly. Removing the headlight assembly requires the removal of the belly pan, front wheel well liner (just the forward section) and the bumper cover. All of that is straightforward to do and takes little time with a cordless nut driver.

3. This will be an opportunity to re-wrap the wire clips on the front bumper cover. The wire loom is held in place using cloth tape on plastic clips. On all of mine the cloth tape had degraded.
The photos show what it looks like with the headlight assembly removed, the assembly in place with the wheel well liner removed, the assembly reinstalled, and the 12 year old bulb and the inside of the failed ballast. Pretty sophisticated headlights!