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Bi-xenon high beam fails intermitently

Discussion in 'E90/E91/E92/E93 (2006-2011)' started by darrinm1, Nov 23, 2015.

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    darrinm1

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    Hello All,

    My car is due for inspection in December and I need to resolve my bi-xenon high beam issue. 2007 E91 with adaptive bi-xenon headlights. I flip the left stalk forward and the bright light indicator comes on and the high beam cut-off flap lifts to expose the full beam, then drops back to low beam, however the indicator still says it is high beam. Is this a loose connection? Bad relay? I have looked around on the internet and all i seem to find are issues dealing with retrofit upgrades from older cars.

    Ideas? Suggestions?

    Thanks,

    Darrin
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    darrinm1

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    MGarrison

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    Cut-off flap? Aren't the low beams 1 light on in each headlight housing, and the brights switch on an additional bulb, and the low beams switch to brighter, so with brights on, 2 bulbs lit in each housing, 4 total? Except for headlights that swivel with steering, not sure there are other moving parts such as cut off flaps? Although I'd think your dash display would indicate burned out bulbs, maybe not - use realoem.com to look up your car. The diagram I saw looked like there's a regular bulb, then the xenon bulb and control unit. Turn on your lights and then look at the front of the car and see what's lit up. The cheap fix would be if the regular bulb is burned out, I'm guessing the more expensive, and, unfortunately, more likely culprit is the expensive xenon bulb, or the even more expensive control unit. If one of the xenon bulbs lights bright and the other doesn't, swap the bright-lit one for the other one and see if it works - if it does, then new xenon bulb. If swapping bulbs doesn't make a difference, then you could try swapping control units to see if that makes any difference. If you find the bulbs good, then you're in for a new control unit. If you have anyplace that can read stored diagnostic codes, that might give a more definitive lead on the exact issue, from a specific error code. If you swap bulbs, you have to handle them carefully, fingerprints or oils from your skin can create hotspots that make the bulb burst when hot. With the bulbs cool, you could wear latex or nitrile gloves to handle them (hot would melt the gloves); clean the bulb glass with rubbing alcohol before installation if the bulbs get smudged or if you touch them.

    Also search http://www.e90post.com/forums/ & bimmerforums.com, if it's a common failure, by now you'll likely find other discussions on it. I don't know how long-lived the xenon bulbs are, but, if they switch to bright and drop back, that would seem like some sort of problem with the control box getting the high-beam signal and keeping the bulb lit on high beams. A typical light relay I wouldn't figure to be your issue, I wouldn't expect a relay to deliver partial power, instead, either on/off.
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    darrinm1

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    MGarrison,

    Thanks for your reply.

    It is definitely the cut off flap that is malfunctioning. I replaced the lamps and balast for both lights about 6 months ago.

    After reading some of the forum pages I decided to check all the easy and obvious things first, like the plugs, wires and switch. With the car on and the engine not running I was not able to recreate the problem. I plugged out and plugged in the connectors to look for corrosion and broken wires. I checked the ground block that sits right there by the fender and headlight module. I saw nothing that was obvious. I was able to cycle the flaps on and of a couple dozen times with no misses. Is it fixed? I suppose I'll see when underway on the road. Maybe there is a loose connection that comes up only when moving down the road.

    Darrin

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