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Auto headlights repeatedly turning on/off

Discussion in 'Model S: Interior & Exterior' started by Bucket22, Apr 17, 2013.

  1. Bucket22

    Bucket22 P85 / #3287

    Joined:
    Mar 9, 2012
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    63
    Location:
    Chicago
    I'm in my 4th month of Model S ownership and haven't had any problems; I've been enjoying the car immensely. Today, I noticed on my drive into work (shortly after sunrise) that my headlights were automatically turning on/off every 15 to 60 seconds for about 10-15 minutes straight. I first noticed it because the ambient lights under the passenger door handle were turning on/off, but I verified based on the reflection on the car in front of me that the headlights themselves were going from DRL to regular headlights frequently as well. I was occasionally going slowly under bridges, and the sky was dimly lit. Obviously, I can turn the headlights on or off manually, but I prefer the auto mode. I'd rather not have drivers in front of me think I'm flashing my lights at them, though I usually am hoping they'll pull right and let me pass. Is this normal automatic headlights behavior in borderline lighting conditions or something that is potentially correctable/adjustable?
     
  2. Al Sherman

    Al Sherman It's about THIS car.

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    I can't really answer any of your questions. I can report (think I asked about it in a previous thread) that my auto lights occasionally stay on when they clearly shouldn't. It isn't chronic, or erratic as you have described but more like every once in a while. They simply stay on as if it were dark. Even in broad sunlight. Each time this has happened when I leave (shut down) the car and come back they work as advertised/expected. No idea why.
     
  3. Doug_G

    Doug_G Lead Moderator

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    I've not had any troubles with the auto headlights. Probably something wrong with the sensor...
     
  4. kvietor

    kvietor Model S S280 VIN 168

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    Dec 12, 2010
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    294
    Location:
    Lithia, FL
    Occasionally, near sunrise or sunset, as I pass under a canopy of trees, the headlights turn on and then off again as I clear the trees. I assume the sensors are set at a certain level of ambient light and I'm just passing in and out of that range.
     
  5. mknox

    mknox Well-Known Member

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    My drive to work lately has been right after sunrise, and I do notice the headlights going on and off more than I think is reasonable. On a couple of occasions, I've manually set them either on or off (depending on conditions) for my drive.

    I believe the sensor acts too quickly. When I pull in to my garage, the headlights will come on before the car is even half way in. My past cars would have to be in the garage and stopped for a period of time before the auto headlights came on. I could usually park and get out of the car before that happened. I think what's happening is when driving at dusk/dawn, the sensor is bouncing between on and off with every little shadow, or when the car turns away from the light on the horizon and the sensor gets shaded a bit. I think this could be fixed in software with a longer delay between "on" and "off".

    I have similar issues with the dash going from day to night mode at dusk/dawn. I think it's just difficult for the car to know what to do when lighting conditions are right on the edge.
     
  6. ckessel

    ckessel Active Member

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    Yep, same here. Just that time of year where my commute matches the sunrise. I don't think it's unreasonable though. Whenever I clear a rise and hit the sun the sensor turns them off, I dip down or a heavy cloud obscures the sun and they come back on.

    I'm good with the sensitivity level. I like when they pop on automatically while I'm in a tunnel even if it's a short tunnel.
     
  7. Doug_G

    Doug_G Lead Moderator

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    Apparently they don't have enough hysteresis in the algorithm. That would solve all such problems.
     
  8. cinergi

    cinergi Active Member

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    What version are you running? This used to be really bad in old versions but is better now. It could still use some work, though. If you're running 4.something, please report it to ownership as feedback.
     
  9. Bucket22

    Bucket22 P85 / #3287

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    Mar 9, 2012
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    Chicago
    I'm running 4.3 and have 4.4 queued up to install tonight.
     

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