Cluster/headlight fuse keeps blowing

Discussion in '6th Generation 2002-2013' started by t90man, Sep 11, 2015.

  1. t90man

    t90man New Member

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    Hello, I am nearing the end of my rope here.
    I started my 2007 VFR Non-ABS after sitting overnight in a parking lot, and the headlight/cluster/taillight fuse was blown.
    I replaced it and it occurred again after a few weeks, this time just sitting in the parking lot at work for 8 hours.
    Now when I turn the ignition key to "ON" the fuse immediately pops.

    Working:
    Fuel pump will run, all turn signals/hazards/horn work fine. I can start the bike and ride it normally using the starter switch.

    Not working:
    Brake lights, highbeam/lowbeam headlights, speedo/lcd on cluster do not turn on. Clock still works though.

    What I've done:
    Connected two wires to the fuse slot with a 12v bulb wired between them. When the ignition is turned to ON the bulb is lit, letting me know there is continuous curent coming from somewhere.
    Unplugging almost every wire on the bike does nothing except for the harness going to the ignition cylinder. Unplugging that harness causes the light to turn off but I think it's because no power is going anywhere at that point.

    Fairings, front cowl and seat are removed currently.

    What I've unplugged to test for short circuit:
    FRONT - cluster, headlights, turn signals, temp sensor, 'blue harness connector', turn signal relay, headlight relays.
    MIDDLE - side stand switch, every harness I can see (fan motor, many shrouded multi pin connectors on LH/RH side)
    REAR - turn signals, brake light, license plate light

    Still to diagnose:
    Regulator rectifier, key cylinder, handlebar switches (not sure how to disconnect)

    Am I on the right track with my test method, has anyone had the same problem, what should I try next?
    Almost ready to roll it outside and leave it on the curb :crushed:

    I'm including a picture of the wiring diagram here to show which circuit I think I am trying to diagnose.
    The green circle means "currently functions normally", red means "suspected faulty part".
    A line through the part means I tried disconnecting it to see if the lightbulb would stop receiving power.

    [​IMG]
     
  2. OOTV

    OOTV Member

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    As weird and unrelated as this sounds, loosen the front brake lever perch and rotate it upward a little. What you're describing sounds very similar to an issue I had and even more recently a few others too. The brake light switch wires, when touching the front fork/clip on, will short out and blow the circuit you're talking about. Typically it only trips the fuse when pulling the brake lever, however I had the same issue with my 5 Gen but at one point the fuse blew regardless of lever action. Fortunately the 5 Gen doesn't blow the dashboard fuse, just the turn signal, brake light and horn fuse, so at least you have lights and a working dashboard.
     
  3. t90man

    t90man New Member

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    I isolated the short to the rear brake light harnesses. Plugging either one of them in causes continuity across the fuse, unplugging them turns off my test bulb.
    So I believe it's possibly related to the lever issue you're describing - however, I unplugged the two little clip on connectors at the front brake light switch AND the harness leading to the rear brake light switch.

    So no brake switches are plugged in and I still have continuity across that fuse terminal ... what's next?

    :lemo:
     
  4. OOTV

    OOTV Member

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    Trace the rear brake light harness and see if it may be shorting against the frame or other ground wire. It's possibly that the wire has been chafed and is shorting out somewhere along the way. That being said, even if the brake light switches have been disconnected, you can't automatically rule out either of those having a short in them. See if you get voltage or continuity from either set of wires as this may determine what set of wires to also trace. That's about the best I can add without dealing with it first hand, wiring/electrical issues are often a hunt and peck process. Good luck finding it, you seem to have a good idea of how to trouble shoot at least.
     
  5. NormK

    NormK New Member

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    As OOTV says you have to find it I'm afraid. You say you have it isolated to the brake circuit wiring in the loom and then you say you have ruled out both switches so that only leaves the damage somewhere in the loom. Try moving the handelbars from one side to the other and see if that changes things up around the steering, you have a wire touching the frame somewhere
     
  6. t90man

    t90man New Member

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    Does this give any useful information?
    Connecting my test bulb across the fuse terminals causes the bulb to light up;
    Shorting the terminals with a solid wire causes the tail lights to turn on and the test bulb to turn off.


    This situation = bulb lit, tail lights off
    (+)|------------(+)fuse terminal
    Bulb
    (-) |------------(-)fuse terminal


    This situation = test bulb off, tail lights on
    solid wire
    (+)|--------(+)---(+)fuse terminal
    Bulb |
    (-) |--------(- )---(-)fuse terminal
     
  7. NormK

    NormK New Member

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    Trying to think how this works and what you are doing, to me if you are connecting one side of a globe to one fuse post and the other side to the other fuse post and the globe lights up it means one side is earthed for current to flow. Think about it connect a globe to the pos only terminal on a battery it won't light up. The next thing that is odd is by connecting across the fuse with a wire and the lights work, does the wire get hot? If not then this indicates to me the fuse you are replacing is not of high enough amps?
     
  8. t90man

    t90man New Member

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    Update on this issue - everything works normally now that it's back together. It seems like the handlebar switches like others had mentioned because I did have to straighten the male terminals where they rubbed against the handlebars.
    The good part is I managed to inspect most of the connectors and harnesses on the bike and nothing else seems to be worn or loose.

    Appreciate all the suggestions!
     
  9. TNRabbit

    TNRabbit New Member

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    Congrats! Electrical gremlins suck donkey balls~
     
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