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Discussion Starter · #1 ·
I've recently noticed a new phenomena; everyday after work I jump in my car (around 6 to 8 pm) and start driving, its definetly sunny out, and bamm headlights ON! I turn them off and then put them back in auto mode and lights come back on. Have any of you guys had this same problem? I've noticed, but i can't confirm yet, but I think this only happens when I have previously set the car to self vent (since its been so hot lately). I wonder if that has anything (software glitch) to do with it. Does anyone know where the daylight sensor is?
 

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Powerfiend said:
I've recently noticed a new phenomena; everyday after work I jump in my car (around 6 to 8 pm) and start driving, its definetly sunny out, and bamm headlights ON! I turn them off and then put them back in auto mode and lights come back on. Have any of you guys had this same problem? I've noticed, but i can't confirm yet, but I think this only happens when I have previously set the car to self vent (since its been so hot lately). I wonder if that has anything (software glitch) to do with it. Does anyone know where the daylight sensor is?
I'm not sure if it has anything to do with that, but on our 760Li, the lights are ALWAYS on, no matter if you have the switch in auto-mode or Off. I'm talking about the left and right lights located next to the air-intake/BMW-sign. I think those are the non-xenon lights.

Did you recently get a software-update? Maybe they extend this "Dayligh-feature" to all previous models, too.

The daylight-sensor should be the little transparent sensor located in the rain-sensor...
 

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Discussion Starter · #3 ·
I wouldn't mind if it was the daylight beams, but this is the actual xenon headlights that are coming on. I bought the car from a BMW dealer (CPO of course) so I haven't had to take it for any service yet, I assume they would've updated all the software during the "certification" process, but who knows? I'm wondering if it isn't some debris or dirt on the windshield that could cause this problem.
 

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Powerfiend said:
I wouldn't mind if it was the daylight beams, but this is the actual xenon headlights that are coming on. I bought the car from a BMW dealer (CPO of course) so I haven't had to take it for any service yet, I assume they would've updated all the software during the "certification" process, but who knows? I'm wondering if it isn't some debris or dirt on the windshield that could cause this problem.
Yes, it sounds to me that it has to be debris or a technical error since the daylight beams def. don't turn on the Xenon lights....
 

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I was told by the service rep that this is by design. The headlights come on when there is an imbalance of the light intensity between the from and the back of the car. It is designed so that the oncoming cars can spot you better when the sun is behind you and could potentially reduce your visibility to the oncoming drivers. It is supposed to be a safty feature associated with the auto mode and can't be disabled and is not related to the daytime running light setting. Mine are generally on during early morning and late afternoon.
 

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Discussion Starter · #6 ·
Now that would explain it best, because its always around sunset that I notice it. I am going to pay more attention to the ambient directional light and report back.
 

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Holein1 said:
I was told by the service rep that this is by design. The headlights come on when there is an imbalance of the light intensity between the from and the back of the car. It is designed so that the oncoming cars can spot you better when the sun is behind you and could potentially reduce your visibility to the oncoming drivers. It is supposed to be a safty feature associated with the auto mode and can't be disabled and is not related to the daytime running light setting. Mine are generally on during early morning and late afternoon.
Thanks, Holein1, for this info!
That reminds me of my favourite statement: "I learned something new today!":thumbup:
 

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I have not noticed that on mine, but I will pay closer attention. Oh by the way, I got to thinking

If your car could travel at the speed of light, would your
headlights work?

vz
 

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light sensitivity

My 03 745i had the same issue. I had the tech try to adjust it with the software settings it wouldn't help. In the winter all but a noon day sun would turn off lights. What was interesting on a cloudy day the lights would work as normal. I finally chalked it up to one of those idiocincracies of the designers.
 

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i noticed the same "problem" today in my 735 (2002)...

i put the lights on automatic and even though the sun was shining the lights were on...

does anyone know more about this? and what can i do to fix it?
 

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Dealer can update sensitivity on the sensor, they usually set on high by the factory, because middle sometimes not working well when you need a light, also look if anything on your window blocking sensor on the mirror
 

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look on ure dash close to the windoshield there should be 2 black circles make sure nothing is covering them . if something is then they will thinks its night out and trigger the lights.plus i like it like that the minute i hit a tunnle they come on no delay
 

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I had similiar problems with my car. It took me 18 months of screwing around with the dealer to get it fixed.

I first noticed that the idrive display was dim sometimes. I had the dealer look at it and they ended up replacing the idrive display (~$3500), but it didn't fix the problem. This was covered by CPO warranty. Another time they replaced the lamp module (~$500).

I continued to complain about the dim idrive display and I then began to notice that my auto headlights were on sometimes during the daytime. The dealer thought I was crazy so they went through the sensitivity adjustment routine just to get me out of their hair. The car was in and out of the shop several times with the "no problem found" result.

I finally made videos of the car with headlights on during the middle of the day while i drove for more than 100 miles to prove to them that it wasn't working correctly. At about the same time, I got a satisfaction survey from BMW on my last service. I reamed them for being in the shop 8 times for the same problems without resolution.

Reaming them on the survey got their attention. They sent in the regional BMW rep and they finally figured out that the rain/light sensor on the windshield wasn't working properly. As it turns out, thie rain/light sensor is not covered by CPO warranty, but they didn't charge me for it (~$150) since they screwed me around so much. The lights work perfectly now. The light sensor not only controls the headlights turning on, but also detects the ambient light levels that cause the idrive (and instrument cluster) to dim and brighten automatically.

What is really sad is that the dealer did probably >$5000 of work on this car when all that was wrong was a $150 sensor. The dealer simply did not know how to diagnose the lighting system on this car, and no error codes were being generated. Thank goodness it was on their dime and not mine.

The rain/light sensor has two light sensors in it. One points up and one points to the front. It uses the signals from those sensors to figure out when to turn the headlights on. I think the "up" sensor primarly controls when the lights come on. The "front" sensor detects other cars. If both sensors don't sense light at the same time, the headlights will be on.

The TIS describes how the lighting system works in great detail. Also the dynamic headlights don't start working until the sensor detects a "really dark" condition which keeps the dynamic lights from operating (and stops wear and tear) when the headlights are on but the dynamic lights wouldn't be useful. The light system will fail safe by turning on the headlights if there is any doubt.

So, if your idrive display ever appears dim in the daylight and your autoheadlights are on in the daylight, the light sensor could very well be the problem. It is certainly the cheapest part in the system!

My SA told me the last time I had the car in for service that they had another car in for the same problem about a month after they fixed mine. They immediately changed the sensor and fixed the problem....
 
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