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b4 80 tdi headlights

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  • b4 80 tdi headlights

    Hi all,

    I'm afraid I know very little about electronics, but any help would be appreciated...

    Basically one night both headlights on my b4 audi 80 tdi went out on dipped beam, but the side lights and full beam were fine. Fuses were fine. So I bought a second hand switch (steering column one with the stalks for indicators and lights) and the lights were fully functioning again. Less than a week later and I've lost dipped beam again. Any thoughts? Is there a relay for the lights somewhere, as I can't find any info about where it is but presume there must be one somewhere. I assume there will be one in the area behind the drivers side parcel shelf thing. Also I suppose it could be possible that the switch has failed as it was second hand?

    Thank you very much in advance for any help!

  • #2
    Sounds exactly like the moment my dipped beam failed. I don't think there actually is a relay on these cars as it is a vag group peculiarity that all the headlight current goes through the stalks. A relay upgrade is something I did on my scirocco to good benefit but not felt the need to do on my b3 coupe yet... The stalks can be dismantled and cleaned, there is a how to on this forum. It is tricky but not impossible and has worked for the last 5 or 6 years for me. If you do it, watch out for springs and small bits that can fall out. You've got spares to practise on so go for it! The fault is caused by tarnished copper contacts unable to pass enough current OR they have relaxed and no long touch where needed.


    • #3
      Thank you so much for taking the time and trouble to help me Steve! That's really brilliant to know what the cause is and I would never have worked that out on my own. I was advised on the classic audi forum to fit relays, and I will also check out the contacts on the stalks as you advised and hopefully that will get my lights back running reliably. Many thanks!


      • #4
        No problem. The relay solution is quite good in that it takes the pressure off the stalks as they only have to handle small amounts of current but they do obviously need to work in the first place. When it comes to 'will relays make your headlights any brighter? , I'm not so sure. If you think about doing it as a performance upgrade rather than extending the life of your stalks, I would recommend mocking up a test loom somehow before buying relays, holders and wire etc... I wired power from battery directly into the back of one headlight as a test and found it didn't really make that much difference. I'm running an alleged upgrade bulb already (Philips silver star) but expected to see some difference at least. There wasn't enough to convince me to go down that route.


        • #5

          Such a shame photo bucket have ruined forum resources by demanding fees for hosting. This was the thread I used for inspiration. A little tricker to follow without pictures ​​​​​


          • #6
            That's brilliant Steve, thank you very much. My headlights work ok (not as good as modern cars, but good enough to see), so I'm not wanting to make them any brighter, but it would be good if there was a fail safe to prevent the switch burning out like this in the future. Also the link to the tutorial thread is excellent so thank you so much for finding it for me, and I entirely agree it's such a shame about photo bucket!

            I hope this isn't a stupid question, but on the lower cowl is a brass ring that makes contact with the steering wheel, presumably for the horn circuit. This doesn't have anything to do with the lights does it, as mine is quite worn so could be making a poor contact.


            • #7
              The brass slip ring you mention is as you think - horn only.


              • #8
                Many thanks Steve, I would have wasted a lot of time without your help! I hope to get them sorted later this week.


                • #9
                  Just to update this for anyone referencing this in the future... Relays fitted and all appears to be well again.

                  Thanks for all the help!