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Electrical Problem - Indicators

Discussion in 'Technical and Troubleshooting Torque' started by Pygmygod, Dec 5, 2014.

  1. Hi All,
    The indicators on our 1989 Honda CBR250 have started to intermittently cease working when you put the brakes on.

    The bike is not blowing any fuses and does everything else fine, but as soon as you put the brakes on the indicators will stop lighting up.
    You can then release your brake lever and pull it in again and it sometimes makes the indicators start to work again.
    Indicators sometimes also cease working when we put the parker lights on and don't touch the brakes at all.

    We've pulled off most of the sticky tape on the wiring harness and can't see any cracked or broken wires and the indicators aren't stuffing up every time you pull the brake lever in so I can't pin-point the issue.

    Also done several continuity tests across the wires and nothing out of the ordinary happened.

    Also disconnected the 2 earths and sandpapered and cleaned them up and re-attached.

    Anyone got some suggestions? Cause I'm stumped and had enough of the damn thing. Only thing I can think of is the lighting circuit is using a shorter ground instead of completing the full circuit therefore the lights are turning off but I don't know how to fix it :(
  2. I am not going to be a real lot of help here. But for me it is an earth problem. Finding it is the hard part.
    • Agree Agree x 2
  3. YOu need an expert. Calling cjvfrcjvfr
  4. I'd be thinking about shorts around the dash...
  5. #5 Pygmygod, Dec 6, 2014
    Last edited: Dec 6, 2014
    We've pulled that to bits tonight, most of the wiring harness tape is off and there's no obvious damage.

    Have cleaned out the switchblock and it's operating correctly.

    Here's the wiring diagram: http://pdfcast.org/pdf/cbr250-mc19-wiring-diagram
  6. Check the charging system output and the battery.....could be a similar problem to older chookies where the combination of headlight, taillight and low revs exceed the charging systems capability and the addition of indicator operation either resulted in either very slow or stalled indicator ( not enough power to excite the flasher can )
    • Like Like x 1
    • Agree Agree x 1
  7. ^what he said

    I'd also be inclined to check the resistance of the wiring through the ground wires back to the battery. The diagram shows multiple connections before it gets back to ground or the regulator. Using a multimeter you should get a reading close to zero ohms. If you're reading more than 1 ohm check the zero on the meter first, make sure you've got good clean test points, and it it's a solid 1 ohm or higher you have a bad/loose/corroded join somewhere. You've only got 12 volts nominal to play with so it doesn't take much in the way of losses to make things work poorly.

    If you absolutely cannot find the problem, try an electronic flasher relay instead of the regular thermal one. They're more forgiving for low current through the blinkers and voltage drop.
    • Like Like x 1
  8. Cheers.
    I'll try out those suggestions.

    The battery is a new lithium one and I don't think the charging system is playing up as it even does the indicator/brake light problem with the headlights completely off.
  9. Checked the ohms from the ground of the rec/reg back to a ground on the frame and it started at about 30 and slowly went down to 0.
    I'm soldering on a shorter ground from the rec/reg straight to the frame, is this advisable?
  10. Easy things to check first - you've already eliminated a weak battery. I'd look next at the connections to the relay.

    Earthing, maybe even the switchgear. Corroded connections to the indicators - needs full voltage to operate the switch to the relay. It's easy enough check whether a simply a voltage drop is causing the fault in the indicators without a meter by operating the high beam, or horn with the indicators going.

    If the headlight or horn do not cause the indicators to stop, then you may have a short in your brake light circuit. this could also be a source of a large voltage drop. Does your brake light work?

    See what the draw (amps) is from the battery when you operate the brake lights to confirm. Does this do it with both brakes or only one?

    I wouldn't be opening any looms or checking any individual wires until I did all of this.

    I haven't got the answer, but that's a reasonable way of going about figuring out what is causing it.
  11. That points to a bad connection somewhere. I couldn't view the diagram you'd attached but does your bike have one signal lamp for the indicators ?
    If it's one it's often used as an earth loop for the indicators. Make sure the signal globe has clean contacts and is solidly connected.
  12. What do you mean by a signal lamp? A globe on the dash to advise your indicators are on?

    Both brake lights via foot & hand levers make the brakes work every time. I'll check the draw today.
  13. Headlight and horn don't cause the indicators to stop every time, only sometimes.

    I had the multimeter on the flasher relay and it had about 14.3V on it then when I had headlights on and brake lights on it dropped to around 12.6V.

    With the bike running the battery had 15V across it and when operating all lights only went down to ~13-14V.

    Another thing I noticed is that if I had the indicators on and the bike running it would even stop or slow the indicators by revving the bike and not pressing brakes or headlights at all.
  14. It is an earth fault. When the brake and tail lights don't have power to them the indicators are getting a sort of earth back through them but when there is power applied to the brake/tail lights there is no longer any earth for the indicators. The electrical circuit diagram shows an electrical layout not a physical one. Just because a few things are shown to be connected in a certain order that is not necessarily how they are connected on the bike. You just have to chase the earth cct and should show almost zero ohms between the indicator light sockets and the negative of the battery whether it uses the frame or wires as the earth return.
  15. Thanks I'll try that next.
    Had just finished pulling the coils and coil bracket off as this is where the frame earth is and wire brushed & sand papered it all back to bare metal.
    Didn't fix it, so will try the ohms from indicator sockets back to battery test.

    One other thing:
    The front indicators aren't the same wattage as the originals, should I find the same wattage bulbs as standard?
    In there are 10W and originals were 18W. We had to buy china knock-offs as the bike had no nose cone or indicators when we bought it due to the previous owner crashing it.
  16. Incorrect wattage bulbs won't cause your problem but it will make the lights flash at an incorrect rate when they are wired up correctly.
  17. Think we might be onto a winner...opened the back right indicator fitting and it looked perfect. Opened the back left indicator fitting and it was rusted all over the earth wire, the bulb housing, even the base of the bulb was rusted!

    Now to source a replacement 'cause it looks beyond what sandpaper could fix.
  18. Have temporarily fit an indicator off of the dirtbike and it appeared to work.
    Took the bike for a ride and the indicators are still temporarily playing up - not as bad as with the old rusty one, but still not 100% fixed.

    Will try and find any dodgy bits behind the dash as the wires are pretty crammed in there and may be a tad squished from when we put the dash back in last time.
  19. Tried new temporary earth wires from the indicators to the frame but they still played up when pressing the brakes.

    Got a new flasher relay coming in the post to see if that helps matters. The old thermal flasher may be on it's way out.
  20. Check the earth circuit for the brake light too.