SV650 constantly blowing "Signal" fuse

[loply]

Hi folks,

After doing some work on the forks my SV650 has developed an electrical problem whereby the "signal" 10a fuse blows every time I turn the ignition on.

Without this fuse my brake lights and clocks dont function (though everything else works fine).

Thusfar I have disconnected all of the following and made no difference:
Indicators | speedo drive | both brake switches | tail light | clocks | headlight.

I've checked the loom for any obvious damage or shorting and I can't see anything.

Any ideas what I should be looking at?

Also, I've heard it's bad to troubleshoot by blowing fuses. I've heard murmurings of using a bulb or a multimeter instead but I don't understand exactly how?

The bike is an 04 SV650S.

Thanks for any help folks!
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Yamaha SZR660 Caution to the wind, the throttle pinned!

[G]

Have you got an alarm that connects to the indicators?

Not the greatest idea, but you can get 'resettable' fuses.

[Chriss]

This isn't really helpful, but more a "let's learn by his mistake" thing, on the GS500, I couldn't work out what was causing a fuse to keep blowing, so I doubled the size of fuse needed.

Next thing I know, the front wiring loom's up in smoke sparking like a good 'um.

Having said that, I found out pretty quickly what was causing it to short out.
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TheShaggyDA: I've got 3 or 4 pairs that predate my wife, so at least 11.5 years old.

[Paddy Blake]

Hmmmnz might be able to help and I can't help at the moment.
Try here to see if you can figure where the problem is.
https://www.bikechatforums.com/viewtopic.php?t=117889

Paddy.

[TUG]

you got led's fitted anywhere on the bike? an alarm? anything else?
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Haz ER-5, innit!

[Keir]

had this on my curvey sv and it turned out to be the indicator wiring by the headstock had shorted. Caused my alarm to constantly go off. Solved by removing headlight and checking every wire for a breakage.
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Current : '08 Yamaha FZ1s
Previous: '99 Honda CBR 600FX, 03 ZX636 B1H, 99 Fazer 600 (red), 02 GSX-R 600 K2, 00 SV650s (red), 2008 ZX10R, 97 Bandit 1200N, 04 ZX6RR K1H, 04 GSX-R 1000, 98 Fazer 600 (gold), 05 Madness 110 Pit bike, 04 CR125R, 00 SV650s (black), 06 KTM 625 SMC, 99 SRAD 600 track bike, 03 SV650, 98 Bandit 1200N, Bandit 600SY, 03 GSX-R 600 K3, 01 GSX-R 600, 01 Fazer 600 (black), VFR 400 NC30 x3, 78 Honda Dream, 00 Speedfight 50

[loply]

I have no aftermarket parts or lights fitted, including no alarm.

I've disconnected everything on the "front" of the bike ie indicators, clocks and all the associated gubbins.

Being as this is quite a young bike, 2004 model w/ less than 10k, the wiring is pretty immaculate, all in its original cable ties and sleeves, and there is no sign of damage
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Yamaha SZR660 Caution to the wind, the throttle pinned!

[finpos]

Trouble is most of the circuits on your bike look like:

batt+ve ----1---> switch ----2----> load ----3----> earth

The short will be around the wires (1) or (2), a short at (3) would do noting. So removing the load or the switch isn't really going to help you.

Connect a bulb up to the fuse holder like this (remove one of the indicators and use that!)

fuse_terminal_1------->Bulb------>fuse_terminal_2

Turn off all the switches on the bike and turn on the ignition.
* the bulb lights up bright - you have a short to earth. Start pulling at things and disconnecting connectors until the light goes out. There's your short.
* the bulb lights up dim - no short, one of your switches is on somewhere.
* the bulb is off - no problem!


f.

[loply]

The bulb idea sounds interesting, thanks for that.

Well, 3 hours later!

I hooked my multimeter between the signal fuse holder and the frame and got continuity - presumeably not meant to be so.

So I basically then removed all bodywork, the tank and the airbox and started disconnecting things.

Eventually I found that when I disconnect the orange connector (behind the radiator) from the main loom that I no longer get continuity between the signal fuse and frame.

This connector is what connects the left hand switchgear into the loom.

I presume that this means that there is a short in the switchgear? Unfortunately I have no fuses left to test for sure, but based on the continuity from the multimeter I reckon this is the source of the problem?

Anyhow, I took the switchgear off and individually tested the orange wires going into it against all other wires going into it, and none of them had continuity - i.e. the orange wire isn't shorting against any of the other wires.

Switchgear is a nightmare to work on, so fiddly!

I'll be buying some fuses tomorrow so I can verify the problem disappears when the switchgear is disconnected, and if it does, then presumeably I need to carefully inspect the inside of the gear for a problem?

Or is the problem still potentially elsewhere in the loom, and it only shows itself when the switchgear is connected somehow? Because inside the switchgear looks a bit too perfect to have a problem - it's very neat and new looking...

Thanks again for any help! I'd really like to be back on the road by the weekend.
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Yamaha SZR660 Caution to the wind, the throttle pinned!

[finpos]

[bugsy46]

Set to continuity, test for continuity between the battery and the the switchgear side of the connector one pin at a time. When you get continuity you should have your shorted wire
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Laura - "And where did looks come into this and bugsy leave steven alone. You are not gods gift to women you may think you are but you're not."
Keith - "All the best"

[Klause]

First off visually check the loom for any rubbing/wear don't forget the signal circuit goes right the way round the bike not just the front.
If your 100% sure you can't find any damage to the loom then Disconnect all the items that draw amps in the signal circuit. Connect them up one by one till you find your fuse blows again. Have you tried disconnecting the indicator/sidestand relay box? At the end of the day it's either a short or a component drawing to many amps.

This wiring diagram could help you... https://www.sv650.org/SV_service_manuals/sv650S-E02-wiring2.JPG

Good luck
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Current bikes: 1960 Triumph 5ta x2, TTR600RE, KTM200EXC, Cagiva Elephant 900ie.

[iooi]

[Chriss]