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I dun sumpin bad... induced a short somewhere in electrical system


angst

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I think I created a short in my electrical system :sad:

I got Darth Blings angled mirror bracket kit with the integrated turn signal mirrors a while back. I really like them but it took me forever to finally put them on. I got around to installing them late last year and in trying to determine how I wanted to wire them (connecting a 2-wire light to VFR 3-wire light), I thought the system was ok with the new lights' positive wires connected to both the running light line and the blinker line. The result was that the new lights were on all the time but still flash as turn signals... this ALSO resulted in the amber running lights being "bright" continuously, the same brightness as they would when flashing, AND the turn signal indicators on the dash were always on but blink when turn signals are on.

The bike was fine for a month or so of riding, and then I blew a fuse recently, the 10A one for the lights/dash. It happened just after pulling out of my driveway so thankfully I wasn't out on the open road with no lights or instrumentation. I went back, replaced the fuse, started her up, and the same thing happened... everything was fine when starting up and then fuse blew after pulling out of driveway.

I suspected that the splice was the cause of the problem, so I cut the wire splices to the running light lines, allowing the new lights to only be on as blinkers. But after doing that and putting a new fuse in, when I started her up, the new lights were STILL ON as running lights but dim. I took the bike out and actually got down the street a little ways before the fuse blew this time.

I believe now that the splice I added between the running light and blinker lines induced an overcurrent in the system somewhere that created a short. With the splice removed, the mirror lights should not be on unless the turn signal is engaged. The other oddity is that those few times I had the bike out and the fuse blew, whenever I grabbed the brake, the lights and dash came back on, as if the brake light switch was bypassing the fuse.

Did I totally hork up my electrical system, or does anyone have any basic troubleshooting steps I can take to find the cause of the problem?

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Sounds like you really borked up something. Cant really help except to say you gotta go to town with a multimeter. Seems it one of those you gotta be there to help (at least for me)

Good luck.

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I've spent a fair bit of time wandering around the VFR wiring system (I re-wired a USA ECU and wiring harness into an Aussie bike's controls).

Basically, you've picked probably the most complex accessories circuit on the bike to mess with. By trying to wire your 2-wire globes into the 3-wire system used for indicating and running lights, you have created all sorts of weird and wacky ways for the electrons to fly around the circuit.

Here's the short summary. Without adding a bunch of diodes, you cannot use your 2-wire globe to act like a 3-wire globe without causing all the problems you have just experienced. If you look closely at a 2006 (and newer) VFR wiring diagram, you will notice they went back to using 2-wire globes in the indicators even when the bike still has running lights. How did they do this? With diodes, that's how. This is why a 2006+ model can use the 2-wire indicator stalks and still have it work on those bikes.

You need to start by remove all the splices. Next, wire up the positive line from the indicator stalks to the relevant positive wire of the indicator/flasher circuit. I recommend wiring the grounds directly to the frame of the bike (not the subframe where the headlight bolts to - but the actual frame). There are some good locations to bolt to up the front; you'll find them.

As for your short circuit, it could well be in the globes on the stalks. A great test for short circuit tracing is to remove the globes from the stalks. If the fuse doesn't blow, you know it's the globes that are faulty and not the wiring. I've seen it plenty of times on cars - the globes internally short circuit themselves somehow. Otherwise it could be the wiring in the stalks or the way you have spliced in the grounds.

P.S. Anyone with decent auto electrical knowledge could knock up a diode system which would let the stalks work as they would on a 2006+ model. You just need the right parts and some knowledge of how three-pin diodes work.

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I've spent a fair bit of time wandering around the VFR wiring system (I re-wired a USA ECU and wiring harness into an Aussie bike's controls).

Basically, you've picked probably the most complex accessories circuit on the bike to mess with. By trying to wire your 2-wire globes into the 3-wire system used for indicating and running lights, you have created all sorts of weird and wacky ways for the electrons to fly around the circuit.

Here's the short summary. Without adding a bunch of diodes, you cannot use your 2-wire globe to act like a 3-wire globe without causing all the problems you have just experienced. If you look closely at a 2006 (and newer) VFR wiring diagram, you will notice they went back to using 2-wire globes in the indicators even when the bike still has running lights. How did they do this? With diodes, that's how. This is why a 2006+ model can use the 2-wire indicator stalks and still have it work on those bikes.

You need to start by remove all the splices. Next, wire up the positive line from the indicator stalks to the relevant positive wire of the indicator/flasher circuit. I recommend wiring the grounds directly to the frame of the bike (not the subframe where the headlight bolts to - but the actual frame). There are some good locations to bolt to up the front; you'll find them.

As for your short circuit, it could well be in the globes on the stalks. A great test for short circuit tracing is to remove the globes from the stalks. If the fuse doesn't blow, you know it's the globes that are faulty and not the wiring. I've seen it plenty of times on cars - the globes internally short circuit themselves somehow. Otherwise it could be the wiring in the stalks or the way you have spliced in the grounds.

P.S. Anyone with decent auto electrical knowledge could knock up a diode system which would let the stalks work as they would on a 2006+ model. You just need the right parts and some knowledge of how three-pin diodes work.

Yeah what he said and double.

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This is a simple fix. Go to Radio Shack and buy some N4001 or similar diodes. Wire them into a V shape where power can only flow to the point of the V. Connect each leg of a V to your turn signal wires and the point of the V to the mirror lights.

I have been running this for years with no issues. PM me if you want a set...it isn't expensive or time consuming.

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This is a simple fix. Go to Radio Shack and buy some N4001 or similar diodes. Wire them into a V shape where power can only flow to the point of the V. Connect each leg of a V to your turn signal wires and the point of the V to the mirror lights.

Like I said, anyone with a decent knowledge of electrics can knock up a solution, and here it is!

It's a bit confusing to picture what he's saying though. I think I can almost picture the circuit but maybe a diagram from Tightwad will help.

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The diodes only conduct positive toward the cathode:

12voltdiodes.gif

This is a schematic for a door chime but it's the same concept...two inputs for one output. Wire the mirrors where it says "to alarm positive door trigger input" and each of the 2 turn signal wires go where it says "positive trigger". Of course you ground the mirror as well.

posdoortrigs.gif

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  • 3 weeks later...

hey Tightwad, thanks for this info... I'll get some diodes and wire it up... thankfully I did pretty well in my circuits lab in school so this makes perfect sense... too bad I didn't do so well as to see what kind of mayhem I'd cause by splicing the two power feeds together in the first place :goofy:

BTW, I finally got some time to start troubleshooting the bike. I disconnected the stem light wiring from the circuit, and I was able to ride around for about 5 minutes with no blown fuses (where originally I got little more than 30 seconds from my house). It's really strange because I tested the stem lights independently and they work fine, and yet with only the one running light power feed going to them, it was still popping the fuse. I took some current readings of the circuit (across the fuse contacts while it was removed) with every combination of turn signals, brake lights, and high-beams on/off, and the largest current draw was about 4A. Then I reconnected the stem lights and the current draw went up to 7.5A!!! Sure enough, I tested one stem light with a 9V battery and it was drawing 2A. I guess with all of the "super bright" LEDs I've got on my bike, I've pushed the current up too much???

Now of course 7.5 < 10 and I'm not sure what could be causing it to spike up above 10 to blow the fuse, but it seems too high. Does anyone know what the "normal" current draw should be on that circuit without a bunch of LEDs or extra lights?

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  • 3 weeks later...

Update: so I tracked down the short.... in the back of the bike =P

When I finally started to search around the bike for anything odd, I looked in the tail-light area and discovered that the license plate light wires had come out of their wire harness plug. Sure enough, I put in a fuse, turned on the ignition, touched the wires together and *pop!*

On the plus side, the problem was caused by a factory plug failing and NOT by something I had done to the bike. On the down side, the problem was caused by a factory plug failing. Hopefully that's the only time.

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