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Electrical Problem : Blown Fuse

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by Rustgold, Oct 6, 2013.

  1. Riding on a rutted road, my bike developed a electrical problem.
    The system in question is on the 15AMP fuse containing the highlight, indicators, brake light, dash lights (neutral etc), & horn (yeah I know, why couldn't they have separated these onto two fuses).

    Anyway, on the day, the fuse blew. All lights work except for the headlight. I thought I must have been the headlight glob (but it wasn't). Even leaving the headlight globe out, the fuse keeps blowing every couple of days.

    If I had any faith in Ipswich's bike shops I'd just take it in, but they'll charge massive sums for their incompetence, so I might as well see if this incompetence ass can fix it himself.

    Anyway, I'm after suggestions on where to look for the problem.

  2. Strip the bike down and follow the harness from the fuse box out and check all the connections, your probably looking for something shorting against the frame.

    Assuming of course you haven't modified the electrical system yourself to add accessory power or something if you have that would be where I look first.
  3. Check where to loom comes out of the headlight housing... maybe the rubber grommet has failed and the wire(s) has rubbed through it's insulation causing the short to earth.

    No doubt vibration has caused this. Check other place like this where the wires do a "turn" around sharp corners.
  4. Go to an autoelec mate, he will trace problem in 2 secs flat.
  5. Wiggle it !
    Trying to find something like this can be a nightmare, see if you can narrow down the area by wiggling the wiring in different areas.
  6. If the headlight hasn't come back after replacing the fuse then the headlight circuit definitely sounds like the culprit.

    The fact that it doesn't necessarily blow fuses immediately but may take a couple of days sound to me like part of the circuit is bare and jiggles to earth from time to time causing a short.

    As others have said try tracing the headlight leads. Don't forget the wiring at the switch too.
  7. it'll be as OP said at the grommet at the exit of the light OR where the loom goes around teh steering head ;) .
    Vibration cused insulation to wear offf and only shorts when moved the right way / vibrates
  8. One trick that I have used to track down an intermittent short, is to remove the fuse and rig up a light bulb at the fuse socket. This way you do not need a handful of fuses. It will light up every time it shorts. But you do need to remove every other bulb/ load in the circuit for this to work. Then just wriggle different parts of the harness watching the bulb for any flickers. The test bulb I use is a 3 watt instrument bulb that fits in a rubber socket with two wires coming out. Replace the connectors on the ends of the wires with spade connectors of same size as your fuse.
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  9. It ended up being a simple bit of bare wire that I couldn't see.
    Thx all.
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