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Stereo doesn't work when it's dark!?

Discussion in 'A3/S3 Forum (8L Chassis)' started by mikec86, Dec 6, 2013.

  1. mikec86
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    mikec86 New Member

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    Hi guys,


    I'm new here and I'm sorry if this is in the wrong forum.


    My problem is a strange one, my stereo(cheap aftermarket) used to work fine, but the memory didn't work. Then after a year or so it started to not work very well at night(crackling as if listening to the radio and the signal is bad). It gradually got worse to the point where it jus wont turn on.


    All of this only happens at night, it works perfectly in the day time.


    I finally pulled it out and wired the 12v memory and 12 ignition correctly and it now keeps its memory correctly but still isn't working at night.


    I decided it must be either temperature or light. Today during the day I had the stereo on and it was working perfectly until I drove into an underground car park and it turned off as if I'd pressed the power button. I hadn't turned anything or or changed anything so it definitely seems to be light affecting it.


    Is there anything that turns on automatically when it's dark on this model? Is it possible(it's highly possible!) that I've still got the wiring wrong?


    When I bought the car it had an after market cassette player that I replaced with the current one and the wiring was awful so I bought a repair kit on eBay and wired it as I thought was correct. I clearly got at least two of the wires the wrong way round so it's very likely there is still something wrong but it seems right to me.


    Any ideas?


    The car is an A3 8L from 1999. It's a 1.9TDi 110bhp.


    Thanks in advance!
    #1
  2. Sham101
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    Sham101 Member

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    get rid ove your car preff scrap
    #2
  3. mikec86
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    mikec86 New Member

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    Haha. Is there a less drastic solution I can try first?
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  4. daz-20vt
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    daz-20vt Well-Known Member

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    Is it not more likely to be interference from something you use in the car when its dark. Your headlights for example. I dont think theres anything on these cars tosensor light or dark. Try it in the day time with your lights on and anything else you can think of thats used at night and not day time.just a thought. Daz
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  5. mikec86
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    mikec86 New Member

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    Thanks daz. I've tried it in the daytime with headlights on, heating on, etc. and I've tried it at night with nothing on. When I went into the underground car park I didn't change anything. No headlights on, nothing, and the radio still switched off. That's why I was thinking of it possibly being a sensor that only triggers when it's dark.

    When I drove out of the car park the stereo started working again. I span the instrument panel illumination dial from max to min so the speedo and clock backlight was turned down and the stereo went off but then I could turn it on again(normally it won't turn on in the dark as if there is no power) changing the illumination did nothing after that first time.

    In short, with everything the same other than the fact that its dark outside the stereo still goes off. Baffling!
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  6. daz-20vt
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    daz-20vt Well-Known Member

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    Is there anything on the unit itself. Thats really odd?
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  7. VAG-Slag
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    VAG-Slag Active Member

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  8. mikec86
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    mikec86 New Member

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    That's brilliant. Nice find!

    @daz: good point. I've borrowed an old unit off a friend. Ill put that in and see how that does this evening. To be honest it's probably the last thing to try. I can't see why the unit would turn off in the dark. And it definitely does seem to be connected to the instrument panel illumination. Every so often it will go off if the brightness for that is changed. Not every time though. I'll report back soon after testing this unit!

    thanks for your help so far!
    #8
  9. T3nnant
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    T3nnant Active Member

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    Don't happen to have aftermarket HID's too?

    It seems to be a lot of interference as when you turn the lights on the signal seems to block the radio.
    mine does it a bit, it will be saved as "capital radio" and when lights on will go to like 105.4 or something
    #9
  10. mikec86
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    mikec86 New Member

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    I have either Philips or osram bulbs in at the moment but I don't think they are the problem. Before it stopped working at night all together it was sounding as if it were playing the radio and getting interference and crackling. At that stage if I pressed the button to put the windows up or down or turned the lights on or put the full beam on it would crackle and the sound would go and then gradually fade back in. However like I said before when I went into the underground carpark yesterday I didn't change anything or put the lights on and it went off. It really does just seen to be the fact that its gone dark.

    I've put the stereo that I borrowed in and that is working fine(as mine does) at the moment. Ill try it again once it goes dark and see if it works. If it does I need a new stereo. If it doesn't then the problem is with the car or wiring.
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  11. kanecullen89
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    kanecullen89 Member

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    I'm not sure if this helps at all but I'm sure my old A3 8P model had a light sensor in the clocks panel.
    When you'd go into a dark area (underground car park etc) the clocks would light up without having to turn the headlights on.

    Could you have possibly hacked into that wire somehow?

    I'm sure in the right light I could see the sensor. It was a small circle at the bottom right hand side of the mph gauge. Just under the 160mph marker to the best of my knowledge
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  12. mikec86
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    mikec86 New Member

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    I think you might actually be a genius... Here's what happened:

    I put the other stereo headunit in and it worked fine(as expected) then I went back out to test it when it was dark, it still worked perfectly several times with lights on and off, indicators on and off, etc. I switched back to my cheapo stereo and it didn't work, I used the torch on my phone and shone it into the sensor you mentioned for a couple of seconds and then the stereo turned on. I set it to play MP3s from my USB stick and it worked perfectly. I removed the torch from shining on the sensor and after about 8 seconds it said "Goodbye..." and turned off. I tried turning it on again and it wouldn't work, after shining the torch on the sensor for a few seconds again it then turned on when I pressed the power button and worked until the light had been removed for about 8 seconds again.

    I tried with the second stereo and that worked again without any torches, so I think it's a combination of a dodgy stereo, and something with that sensor, anyone have any idea where the wire for the sensor is and what colour it is?

    Thanks again for all the help so far!
    #12
  13. 16Klappe
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    16Klappe Princess Slayer

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    Other than an auto dimming rear view mirror which was a factory fit option and is totally self contained there is no light sensor AT ALL in ANY 8L car, none. Not a single light dependant sensor that is connected to the central electrics.

    8P's on the other hand do have light sensors built into their interiors which leads me to believe you are in the wrong section.

    8L's however don't, so I am a bit confused about this "sensor" you are shining your torch into. Where exactly is it?
    #13
  14. mikec86
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    mikec86 New Member

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    What are you saying? Either that isn't a light sensor on my dashboard or I don't have an 8L? I'm pretty sure it is 8L though. It's a 99 model so it's a facelift I think, does that change anything? Also it's an Italian car imported into Spain, could it be different spec to the UK?
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  15. 16Klappe
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    16Klappe Princess Slayer

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    Could be. Highly unlikely.

    It could be a facelift, but again not likely as a 99. Does it have one or two piece lights? Digital or analog interior clock? Rounded door handles or flat ones sunk into the door?

    I would be astounded if there was a light sensor on the clocks of your A3, because I have NEVER seen or heard of a single light sensor on any 8L. They don't have that function.

    If it is a EU car that's been imported into Spain, then the spec may differ. But I can't imagine Audi putting an interior convenience on their car and not rolling it across the whole range.
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  16. mikec86
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    mikec86 New Member

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    I'm having an absolute mental block here. Ill take some photos tomorrow. What I do know is that the handles are flush with the door and its an analog clock. This guy posted a photo of his speedometer: http://www.audi-sport.net/vb/a3-s3-...r-lights-8p-s3-style**-pics**.html#post894819 I'm pretty sure that's the same as mine. The 'sensor' is in the lower section on the speedo on the left of the mileage/tripometer thing. There's a clearly visible circle there.

    ill take photos and post the. Tomorrow if this doesn't help. Ill also check the VIN.
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  17. 16Klappe
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    16Klappe Princess Slayer

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    Pre facelift car.

    I know the little circle you mean, all of my 8L's and every one I have been in have it.

    It doesn't do anything though, certainly not on Uk models. So if it is a light sensor, none of us will be able to help you.
    #17
  18. Vex182
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    Vex182 Guess what I drive...

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    That sensor under the 0mph controls the brightness of your backlight on the dash. I have just tried it, if I dim the lights down to the minimum and then shine a torch to it, the lights all brighten up on the dash and I have to turn the dial up to max brightness and then back down to make it go dim again.
    #18
  19. Vex182
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    Vex182 Guess what I drive...

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    Actually I now just noticed that is goes back to dim slowly itself when you turn the torch off.
    #19
  20. 16Klappe
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    16Klappe Princess Slayer

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    Yours is Facelift.

    Is that for real? Does it really, because if I am wrong about this then the entire forum will need proof.

    Video it.

    Xxx
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  21. Vex182
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    Vex182 Guess what I drive...

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    Really does it. I'll try and video it.
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  22. 16Klappe
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    16Klappe Princess Slayer

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    **** my life.
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  23. Vex182
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    Vex182 Guess what I drive...

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    There is the sensor:

    [​IMG]
    #23
  24. 16Klappe
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    16Klappe Princess Slayer

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    I know it's there, but never knew it did anything.
    #24
  25. Vex182
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    Vex182 Guess what I drive...

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    [​IMG]
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  26. Vex182
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    Vex182 Guess what I drive...

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    Can't find a way to upload the video to photobucket?
    #26
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  27. Vex182
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    Vex182 Guess what I drive...

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    Done it!

    [​IMG]
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  28. 16Klappe
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    16Klappe Princess Slayer

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    That's amazing.

    I bet there isn't anyone on here who actually knew that, I'm not even mad that I was wrong, it's just amazing.
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  29. mikec86
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    mikec86 New Member

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    Wow thanks Vex, I was starting to question if I was imagining the stereo working when I did shone the torch into it!

    So I'm guessing that if only one person knew this existed, nobody is going to know how it is wired up and how it could affect a stereo. What a weird problem...

    I'm wondering if it is something to do with the 12v memory wire. I had them the wrong way round so the stereo was working but not storing stations etc when the ignition was turned off. I've now put it right and its only since then that it turns off when dark(before it was just sounding really bad and crackling at night time). Is there any way something could be interfering with the 12v ignition wire? If I posted a photo of the wiring as it is now will anyone be able to tell what each wire is? I'll try and get a good photo of the wires and connectors and upload it later.
    thanks again for all your help guys!
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  30. :: blade ::
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    :: blade :: Member

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    my radio goes fuzzy when i put tje rear demist on :(
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  31. JoeeS3
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    JoeeS3 Active Member

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    not sure if you would want to do this but my stereo stopped working in my a3 8l before and it was due to the +12v wire being a bit dodgey with aftermarket stereos. all i did was feed a wire directly from the positive terminal of the battery to the +12v of the stereo and never had a problem with it, i just had to manually turn the stereo off everytime i turned the car off.
    #31
  32. mikec86
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    mikec86 New Member

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    Ok I have ordered a new stereo and that should arrive later in the week, in the mean time here is the sensor on my speedo:

    [​IMG]

    Can anyone help with the wiring? I almost certainly have this wrong, but this is what I have at the moment and what I think each wire is. Here's the ISO Connector going to my stereo:
    [​IMG]

    Here's the connection from the ISO connector to the car wires:
    [​IMG]

    And here is a better image of the wires in the car:
    [​IMG]

    I accidentally pulled out what I think should be the ground wire when I was taking the photo, so ignore that!

    Any ideas if this is correct?
    #32
  33. mikec86
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    mikec86 New Member

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    Im not sure I'd be comfortable doing that. However would wiring the memory wire into both the memory and ignition not have the same results? I might try that if I continue to have the same problem with the new stereo.

    I'm still not convince I have the wiring correct though.
    #33
  34. JoeeS3
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    JoeeS3 Active Member

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    i honestly couldn't tell you. i just found it the easiest way of doing it was directly to the battery as you know it is 100% getting power to it. just dont forget to turn the stereo off once you turn the engine off if you do go down that root. i dont see why what you said would not work though
    #34
  35. mikec86
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    mikec86 New Member

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    Ok thanks for that Joee!

    Anyone know if I have the wiring correct? Do my notes on the images look right?

    Thanks again!
    #35

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