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20A fuse keeps blowing - any ideas why?

Discussion in 'XJ Technical Chat' started by baz666, Aug 11, 2008.

  1. baz666

    baz666 Member

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    Maybe someone can help with this problem on my 81 XJ650 Maxim.

    The 20A fuse that runs the signal lights, neutral light and the like keeps blowing every few weeks.
    At first I thought it was because it was getting wet since the first few times it happened during rain showers.
    But today the fuse blew in dry, sunny weather.
    Any ideas on what I should be looking for as a remedy?
    thx,
    baz
     
  2. jriebe

    jriebe Member

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    Could it be shorting out on anything? I have heard that YICS fuseboxes are quite notorious for blowing fuses..
     
  3. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    20A for lights? Is the 650 that different than the 550? My 550's have a 20A MAIN, all others are 10's (as far as I know...) Do you have the original poor excuse for a fuse block? Otherwise, might be time to take a look in the alternator, how many miles on the bike?
     
  4. baz666

    baz666 Member

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    Sorry, I meant a 10A fuse, not 20A. The 20A is the main while the rest are all 10A.
     
  5. baz666

    baz666 Member

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    I hate to admit I still have the original glass barrel fuse set up provided by the folks at Yam. I guess it really is time to switch over the blade type fuses. I've already done it on the XJ900, so now it's the XJ650's turn. But the wires are pretty brittle near the fuse box. I guess that means I must strip the harness down to the point where the wire seems to be in good shape. Is that a correct assumption?
     
  6. wizard

    wizard Active Member

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    Yes & a good idea also, I kept with the original length wires & it's tight, if I was to have to do it again I would splice on new wires, gives you more flexability for possitioning.
     
  7. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    If you have Radio Shack stores up there in the Great White North <joke, I'm almost due west> pick up a couple of 270-739 "chassis type fuse holders" and liberate the contacts from their plastic base. The contacts are a dead ringer (although a bit "squatter") for the original fuse holder contacts but not made of that brittle white metal...they will even 'snap' into the original fuse block. Good interim fix until retrofit...
     
  8. RickCoMatic

    RickCoMatic Well-Known Member

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    There's no sense trying to fight with the just the length of wire left behind after a Fuse Panel is cut out.

    Solder some extensions on to the short ones coming off the bundled side.
    Solder some extensions on to the long side, too ... and you can maneuver the New Fuse Panel to fit where ever you want to put it,, then.

    Once you get the whole thing wired after adding the extensions ... all you have to do is wrap-up the NEW wiring with some Black Tape and you got it solidly built and looking good too!
     
  9. Polock

    Polock Well-Known Member

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    the fuse block is doing what it's supposed to do
    you have a problem in that circuit and a fuse block from the space shuttle won't help if you don't find it
     
  10. baz666

    baz666 Member

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    I'm wondering if a malfunctioning aftermarket flasher relay would cause the 10A signal fuse to blow.

    When the stock flasher relay bit the dust, I bought one of those cheap aftermarket automotive jobs. The little silver colored barrel shaped thing. It was something like $2.99.
    Anyway, it worked fine for a couple of years - until yesterday. After disconnecting and cleaning the relay unit, I plugged it back in, turn the ignition key to the on position and tried the signal light switch. The 10A fuse blew soon as I tried using the turn signal. The female flasher relay connectors going to the wiring harness show 12V power with no variation. However, the continuity test on the aftermarket flasher relay was off the charts on the multi-meter. I think it's supposed to be somewhere in the middle.
    Any help would be appreciated.
     
  11. switch263

    switch263 Member

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    What do you mean off the charts? Full continuity across all terminals? No resistance? Obvious short? Tons of resistance?

    I had a malfunctioning flasher relay in my 88 camaro that played havoc with my entire ignition system because of how it all was wired. Relay shorted to ground, I lost spark. Definately worth checking out, especially if it's only a few bucks!
     
  12. RickCoMatic

    RickCoMatic Well-Known Member

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    For $2.99 for the Flasher ...
    I'm pulling it and see how far I could whack it with a 32-Ounce Louisville Slugger!

    The only test would be how well I made contact with the Baseball Bat by how far it went.

    Good contact and it probably don't go to far ... right?
    It would just flatten-out and die or disintegrate.
     
  13. baz666

    baz666 Member

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    Actually, the flasher turned out to be okay. After much futzing about I'm suspecting a short somewhere, an exposed wire rubbing on metal, a loose connection or something. Only because evertime I put in a new 10A fuse, plug in the flasher, turn on the ignition and hit the turn signal switch, the fuse blows.
    Short circuit, right?
     
  14. shogunl

    shogunl Member

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    I had problems with fuses also. But I could not find blade type fusebox anywhere around here in great white north.
    After some puttering around I went to Canadian Tire and bought glass type fuse holder and heat shrink for around $10 CDN.
    Removed old fuse holder put heat shrink around the wires to ensure they don't contact each other then solder in the new fuse block.
    Let see how this works out.
    I know I know I should have used blade type but damn it guys we just can't seem to get some stuff up here that can be had in the US.
     
  15. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    I dunno, the flasher could be drawing too much juice just to activate its "clicky thing" how are you sure the budget relay is OK? I agree with Rick, but I'd run over it instead...or bash it with a hammer...but in answer to your actual question, it could be a dead short somewhere in the turn signal circuit, but I'll bet you it doesn't matter whether it's right or left, does it? If it DOESN'T matter, it narrows your troubleshooting down immensely, plus it points back to the cheapo relay...
     
  16. baz666

    baz666 Member

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    Well, the cheapo relay is one theory but I put that to rest by swapping in the signal relay from my XJ900, which is exactly the same as the stock relay on my XJ650. It works fine on the XJ900, so I know it works. But when I plug it into the XJ650, I get flashing on the left turn signal then clicking and no flashing on the right signal. A few times trying that and the 10A signal fuse blows. The other thing is when I check the voltage coming through all fuse clips, I get 12V on all clips except for the negative clip on the 10A signal fuse. On that I get what looks like about half the normal voltage. I'm just not sure what all this means.
    Any help would be appreciated.
    thx,
    baz
     
  17. baz666

    baz666 Member

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    After extensive multi-meter testing here's the deal:

    I DO have 12V power at the signal relay plug that's just beneath the ignition coils.

    I've got NO power at the front turn signals wire ends where the front signals actually plug up.

    I've got NO power at the headlight plug, hence no headlight, which is illegal.

    I've DO have 12V power at the auxilliary light plugs inside the headlight casing.

    I've DO have 12V power at both ends of all fuse clips.

    I've got NO power at the rear turn signal plugs, which are under the seat, just rear of the storage tray.

    I've DO have 12V power at the tail light/brake light plugs, which are also under the seat, just rear of the storage tray.


    If you've got any idea where I should look to solve the problem, please speak up.

    And a question. Can I plug the headlight into the auxilliary light plugs inside the headlight casing as an emergency measure until I get the headlight power supply restored?
     
  18. Polock

    Polock Well-Known Member

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    I DO have 12V power at the signal relay plug that's just beneath the ignition coils.

    I've got NO power at the front turn signals wire ends where the front signals actually plug up.
    no power here till the signal is on
    I've got NO power at the headlight plug, hence no headlight, which is illegal.
    high low or both, might be a different problem
    I've DO have 12V power at the auxilliary light plugs inside the headlight casing.
    i don't see these on the drawing
    I've DO have 12V power at both ends of all fuse clips.

    I've got NO power at the rear turn signal plugs, which are under the seat, just rear of the storage tray.
    same as front
    I've DO have 12V power at the tail light/brake light plugs, which are also under the seat, just rear of the storage tray.
    different circuit

    check out the switches on the bars, be careful of flying tiny things
    where the wires bend at the steering neck is a good place to look
     
  19. baz666

    baz666 Member

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    Thanks Polock, I'll check it out.
    The "auxilliary" light plug has two round prongs inside a plastic sleeve and on my 81 XJ650 has a light blue wire running to the connectors. When I plug the turn signals into this "auxilliary" feed, they light up if the ignition key is turned on.
    The same thing happens when I plug the headlight into this "auxilliary" feed.
    The headlight comes on soon as the ignition is turned on and appears to be of normal brightness. Normally, the headlight on my XJ650 doesn't come on until I start the bike up.
    But on my XJ900, the headlight comes on soon as I turn on the ignition key to "On" without starting up the bike.
    I'm guessing this extra "auxilliary" power feed inside the headlight casing is related to that somehow.
     
  20. bill

    bill Active Member

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    I have the same plugs- my assumption is that are so you can replace the 1156s with 1157s int he turn signals and have running lights. would have to replace the light socket also.

    The head light turns on when the engine is running via a relay. You may want to see if it is bad. I would have to check my manual but I believe the headlight has a dedicated circuit and heavier wire due to current draw, not sure about that but you should check it out before running that way. You could cause the wires to overheat and have another short issue or worse.
     

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