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900ss Tail Bulb Electrics

Discussion in 'Technical Help' started by Humbug, Feb 19, 2017.

  1. Hello!

    My tail bulb will illuminate the stop light but not the main filament.

    Just changed the bulb, didn't solve the issue.

    Rest of the electrics are 100% (including the headlight).

    Bike is 99% standard and kept out of the elements, so I'm really not sure what's caused this.

    Please help suggest the solution!

    Cheers,

    Humbug
     
  2. Is the bulb in the right way round? I seem to remember that on these bikes it's possible to fit it 180ยบ out.
     
    • Agree Agree x 3
  3. the only time I had identical symptoms it was either the brass-type contact within the bulb holder losing its tension and/or becoming lightly tarnished.
    The leady-solder on bulbs mostly available today have a smaller 'mound' than 20 years ago, have even built them up with solder before to cure the 'tension' or reach problem.
     
  4. There's resistance to putting in the bulb 180 degrees out, so I think it only goes in one way.

    Contacts look clean, but i'll scuff them up a bit and give it another go.

    Might the fault be elsewhere on the bike?
     
  5. There are some single wire connectors on route, a meter or bulb tester might save time. So no light with either front or rear brake applied I am taking for granted, the chances of both brake light switches failing are rare.
     
  6. Hi There is a multipin connector for the rear tailight loom,its located under the seat next to the mudguard mounting point. check that this is clean and secure, if you have a voltmeter check the supply to pins d and e.
     
  7. For the record, the (live) brake light wire supply to that plug is usually yellow and it goes to connection position 'D' (numbers are often difficult to make out though)

    'E' connection is for the sidelight circuit, (grey/red snake).
     
  8. Is it the correct stop/tail bulb??

    If so, it should have offset/staggered pins and will definitely only go in one way round
     
  9. I wasn't going to dive into this, but the thread seems to have gone cold so I thought I'd ask if you got it solved...

    If not can you tell us what happens to the tail light when you put on the main or side lights, does it work?
    In that condition what happens to the brake light, nothing or does the brake light work

    I'm wondering about earths as this can cause all sorts of mayhem if it's badly grounded or missing
     
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  10. Hi Old Jock,

    Not got it solved - I was travelling last week for work so haven't got a chance to get to the bike.

    Symptoms:

    Tail light doesn't come on with the main light, and the stop light only operates when either brake is applied.

    I've got a multimeter, but I only use it to check voltage. I'm embarrased to admit not knowing how to check for continuity, though I'm more than willing to give it a go this weekend.
     
  11. I'll give it a bit of thought and get back to you if I can think of something, I'll need to draw out, what is admittedly a pretty simple, circuit to see if I can figure out what might be happening.

    Just replying now to say continuity checking is easy, don't switch on the lights, set the multimeter to Ohms and then apply the test leads to the points you wish to check for continuity.

    If you get a high or infinity reading on the Ohms scale then the connection is broken, if its low or close to zero then you have continuity i.e. a continuous electrical path.

    The reason you do this with the circuit dead is the meter uses its internal battery to put a voltage on the line and measures the current flowing through the line and resistance can be determined from knowing this. Volts=Amps/Resistance

    If the system already has a voltage on it, the readings will be unreliable, 12V shouldn't harm a meter but I've seen guys do something similar on house mains and blow the meter to bits.
     
  12. Hi - I found the multipin connector on the left hand side of the vehicle above the mudguard. It looked in good condition, and was full of vaseline.

    I gave it and the bulb holder a quick squirt of contact cleaner.

    if the connector is lettered:

    abc
    def

    then:

    a- empty b-continuity to right hand pin of bulb holder c- continuity to left hand pin of bulb holder
    d-continuity to right hand pin of bulb holder e-continuity to right hand pin of bulb holder f-continuity to right hand pin of bulb holder

    That's as far as I got!
     
  13. Ok I'll need to get a wiring diagram from the web.

    One thing however that could be your problem right there is the Vaseline.

    Vaseline is often used on connectors and battery terminals to prevent corrosion, but IMHO its a BAD idea.

    Its a dielectric meaning it does NOT conduct electricity. If it gets onto the pins it can cause all sorts of grief.

    I'd first try getting the connector and pins apart and clean off all the Vaseline then recheck.

    Personally I occasionally use Vaseline or dielectric grease very sparingly is on the battery terminals to prevent corrosion.

    John
     
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  14. Have we had any confirmation yet that the bulb is the correct stop/tail bulb with dual, intact filaments and offset/staggered pins?
    If the bulb is not the correct one, everything else is a total waste of time.
     
  15. The original bulb looks perfect, so does the replacement, but I agree, there's the possibility they're both duff.

    I'm off now to buy a couple more from the local garage and try them.

    Cheers,

    Humbug
     
  16. It has to be a stop/tail bulb with dual filaments and offset pins!
     
  17. Yes, they are! Bulbs no. 3 and 4 also didn't work, but I have found out what's wrong.

    I traced the wiring loom the other side of the six pin connector - ie towards the tank, and found a partial split in the loom a few inches further up by the shock - you can see copper filaments through the split.

    What's my best option please - take it to a bike shop to repair the loom, or completely replace this loom?

    Thanks for everyone's help so far.

    Humbug
     
  18. No need to replace the loom. I would open up the loom at the point where the damage is. Cut out the damaged cable and solder in a new section with heat shrink tubing over the joins at each end. Then re-wrap the loom with proper loom tape. Re-route the loom if possible to avoid future damage and/or fit sleeving at that point to protect it.
     
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