SV650S 1st gen: 15A SIGNAL fuse keeps blowing when switched from neutral to 1st gear.

Lads and lassies,
Leaving work last night I did my pre-ride checks on lights, indos, breaklights etc. All working fine. When I put the bike in 1st gear (engine running, ready to go) all dash went dark, no clocks, no indos, horn. Headlamp and hi beam still operational, when put on high beam blue indicator on dash worked.
Needless to say, it was wee stressful to ride home in the evening traffic without stop light and indos, so hand/leg signals and leftmost lane for me.
I came back home, opened up a fusebox, upon investigation 15A fuse blown, I replaced it, dash came back no problem.

This morning I started the bike as usual, all lights working, ready to go, pop into 1st, headlight flickered for 1-2s and puff, same as yesterday.

I can still start a bike no problem, so all ignition signals from sidestand/clutch switches are working as intended.

I looked into wiring diagram in Haynes and by the looks of it fuse no. 4 (this is 15A signal one) wires to the neutral gear indicator via diode in indo/sidestand relay. I don't know what exactly happens in neutral gear switch when selecting a gear, but I assume it inverts current flow direction that diode should stop it, and N light on a dash switches off. But if for some reason this diode goes trough brakedown in reversed polarity then current is probably too high and blows the fuse. Having written it now, I realised I can easily check diodes with multimeter for breakdown, whatt'ya think?

Any input my fellow SVers?? This bike is me only way of transportation.

Ride safe
Greg

[Blapper]

I'd start by checking the looms for signs of old age - insulation worn through? If your bike's a daily rider, it is probably pretty dirty so the grit can help the abrasion of the wires.

How many miles?

[daktulos]

It sounds like a short - have you checked for water in any of the connectors or switches or ICU? If you've not got the full wiring diagram, this one should be useful:

http://s214.photobucket.com/user/coe...e-1-1.jpg.html

Cheers lads. Yea the bike is 60k kms and I was caught in the torrential rain yesterday morning. I'm gonna check the relay diode and neutral switch for shorts/open circuits as per Haynes to exclude failures there. Then I am gonna check the loom from fuse 4 up looking at the schematic (thanks Daktulos) I can see I have to revisit few connector blocks, I will see if there's any water in them. But I can see it's gonna be a royal PITA to find any fraying in all this network.

Keep it coming...

Update #1: I disconnected neutral sensor and fuse blown again, thus it's not a sensor.

[Seeker]

Your bike blows a fuse when put into gear.

You disconnect the neutral switch and it still blows the fuse when put into gear.

How does it know it's in gear?

That's weird (and shows I know even less about bike electrics than I thought).

Maybe it's a time related issue and not a gear related issue?

Instead of the gear, could it be something to do with the clutch switch? To my knowledge thats the only other switch/sensor affected when changing into first. Im probably wrong though :P

[daktulos]

Originally Posted by Seeker

Your bike blows a fuse when put into gear.

You disconnect the neutral switch and it still blows the fuse when put into gear.

How does it know it's in gear?

That's weird (and shows I know even less about bike electrics than I thought).

Maybe it's a time related issue and not a gear related issue?

That's exactly what I was thinking.

When put into gear, there will be a small load placed on the engine as (on my curvy anyway) the clutch is not perfect. I guess this could cause an impulse through the alternator ... but if it was the cause there wouldn't be a couple of seconds of flickering.

Related to this, I always have the front brake engaged when going into first. It would be worth considering what else you may do before changing gear, in case there's something subconscious like this. It's certainly worth trying all the controls for a good amount of time to see what happens.

Originally Posted by Seeker

Your bike blows a fuse when put into gear.
How does it know it's in gear?

If you don't have a sensor it always assume it's in gear - open circuit. To start it you have to fold the side stand.

I am an electronic engineer so I'm handy with multimeters, soldering etc. I am sure it is a short, the question is where tho. I assume "ohmic" contact, not a pure short - the fuse is not blown immediately but rather after some time. Plust main 10A fuse is not blown as it's larger in size, hence can take larger current for longer than mini 15A fuse that has less metal.

Also the fact 15A is blown, shows the short is located somewhere after it. I think the fact it blew when I put bike in gear was just a coincidence, yesterday it blew after I moved and did 100m or so.

If you don't mind, I'm gonna post the updates with, hopefully, the final result for future reference.

Greg

Originally Posted by daktulos

It's certainly worth trying all the controls for a good amount of time to see what happens.

Good point. My "muscle memory" is clutch lever pulled in + rear brake. Then split second leg change to put it into gear and back to the rear brake. Then slowly releasing the clutch and rear brake for soft roll forwards. This is how I was thought on my basic training. Headlights on and dash illuminated but that's about all.