BMW E36 Blog

Turning Your BMW Lights On Automatically At Night . . . System Testing

24th March 2008

Turning Your BMW Lights On Automatically At Night . . . System Testing

posted in Electrical, Technical Info, Tips & Tricks, Uncategorized, Videos |

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As I promised in my previous post Turning Your BMW Lights On Automatically At Night . . . Soldering, I connected the autolight circuit to the car and decided to put it into the test. But before jumping into the test videos, I will try to summarize what I’ve done through this project in case someone has missed my previous posts.

I wrote five articles until now about how you can make your BMW lights turn on automatically at night. In the first post, I proved that this should be something easy to implement inside a BMW E36 car. In the second post, I presented a circuit diagram that will help you create the electronic circuit that is supposed to control your lights and turn them on automatically when it gets dark. Of course, if you don’t know how to implement such a circuit or you simply feeling too lazy to do it, you can ask some electrician to do it for you. I’m sure he will agree if you paid him $20. In the third post, I wrote about my first attempt to implement this circuit and told you that it’s partially working but it needed some enhancements. In the fourth post, I created a video with the circuit implemented on breadboard and connected directly to my brother’s car lights. In the fifth post, I soldered the circuit on permanent board and showed you exactly how I intend to use it inside my car.

Ok, now I hope you’re ready to watch the test videos for the autolight project. The videos were shot by my wife while I was driving the car. As you can see, it is not dark yet, so I had to go under some tunnels to show you how it’s going to work.

In the next video, you will see the light sensor (it’s ugly I know) which is responsible for sending the proper signal to the control circuit when it gets dark. You can see also that I used the tail light switch to enable/disable the autolight circuit (temporarily):

Take a look :-

In the next videos, I’m showing the car in different situations and how the autolight circuit is responding correctly to the light changes. You will need to pay special attention to notice the changes when the dashboard lights are turned on then off again.

For your information, I’ve burned something while doing the installation of the circuit … can you figure out what it is?

Now, I’m sure that you have a burning question in your mind. Tony, why you didn’t take a shot of the car while driving from outside to show us how the headlights are working? To be honest with you all, until now I figured how I can turn the lights of the angle lights (the circles) and the dashboard lights.

I couldn’t figure out why the headlights didn’t work correctly. It seems I didn’t connect the correct wires and because I was rushing to take the videos before it gets dark, I decided to do this next week :-).

Oh yes, one last thing. If you have any comments about how I can enhance this more or you know how the headlights are controlled by the headlight switch (what is the color of the wires), please let me know. this is the only thing that I still need to to figure out before having a complete auto-light system in my car 😈


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There are currently 5 responses to “Turning Your BMW Lights On Automatically At Night . . . System Testing”

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  1. 1 On April 8th, 2008, John said:

    Nice work. I think the light sensor on new BMW’s is installed behind the rear view mirror, against the windshield glass. I think a nice enhancement would be to add a polling circuit to the sensor switch, which would check the prevailing light conditions 5 and 10 seconds (or some reasonable time period) after the initial light condition change, so that extra power cycles to the lamp circuit could be minimized. This would probably be important if you have installed HID lights in your E36. Putting a load on the lamp circuit, then taking it away right away is probably not a good thing for the circuit.

  2. 2 On April 8th, 2008, Tony Sticks said:

    Thanks John for the message. In the current circuit, I don’t use any delay or timing components. Until now, I didn’t need it except for one time when it was like getting dark but not very dark, so, the dashboard lights flickered for a second then it went away. This is the only time that I’ve seen this problem but I’m 100% sure that the timing component is absolutely necessary.

    What I’m considering now is:
    1. To complete the installation so that it would work for the headlights, not just for the dashboard and the angel eyes. I didn’t have time last week to do it, so I hope I will do it this weekend.
    2. To find a proper place to put the sensor in a way that looks pro. I don’t think that I can put it behind the rear view mirror because it will mean that I will have to wire it all over the top of the car and I don’t think this would be a good idea.
    3. I’m considering the implementation of a dual auto-light system. In which, the angel eyes + the dashboard will turn on automatically when it starts to get dark. The headlights however will be turned on when it gets really dark. How is that?
    4. In the dual system, I will make sure that the flickering problem is solved. After all, I’m sure that the headlights (HID especially) will not like flickering at all.

  3. 3 On April 9th, 2008, John said:

    There are other locations to install the sensor, one being
    front of the dashboard. Someone with an E32 did this. To me,
    it looks homebrewed, not something factory. The other location
    for the photocell I’ve seen was to wedge it between the dashboard
    and glass. Again, not very professional looking.

    You would be pretty surprised at how easy, and quick it is to run the
    length of wire necessary to install the photocell behind the mirror.
    New BMW’s have it there. I installed the Hella rain sensor for E36,
    and had to run the supplied wire from a location under the dash to the
    back of the mirror. It was very easy – just pull the pillar cover straight
    out, then run the remaining length of wire under the headliner by pulling it
    down slightly. It took less than 5 minutes to do all this.

    I’d be interested to see how well the delay circuit works. The power draw for
    HID’s is pretty high on startup, so preventing the light from turning on and off
    alot would be very good for your wire harness.

  4. 4 On April 9th, 2008, Tony Sticks said:

    Hi John,

    I’m considering other alternatives instead of puting the light sensor on the rear view mirror because I don’t see why it should be there and not in another place. That’s why I’m trying to find a better spot (maybe on the dashboard somehow). Maybe the air vents. I’m still looking.

    About the delay circuit, I will definitely write about it when I implement the circuit.

    Do you have any experience with electronics John?

  5. 5 On February 10th, 2011, matt said: