Fuse Blows when breaking

[Hypocycloid3]

Was just hoping somebody has encountered this exact thing before so I can stop unraveling parts of my wiring harness looking for a short.

Whenever I use the break circuit, weather it's the hand break or the foot break... my headlight dims, no break lights, and if lever/pedal is held down for more then a few seconds... the second fuse,(first 10a) in line consistently blows. I thought the short was in the turn signal switch unit and replaced it. No change. Got new replacements for both stop light switches on order just for good measure because they have been though thousands of miles on my '94 anyway but I don't suspect that's where the problem is so any ideas are welcome. Thanks in advance.

Oh, forgot to mention... I can get turn signals and running lights, neutral indicator light etc. until either that fuse blows or as long as I have both break switches disconnected and leads taped off.

 

[06VMAXIMUS]

Sounds like the hot wire is grounding out. Since it happens with either your foot or hand, I'd have to say its downstream from both of them.

 

[PDWeyand]

Pull your pillon seat and look from light backwards towards the front. A chaffed wire could be right at the main wiring point under the rear seat, the wires run right next to the frame there and the middle part that moves could have opened a bear spot in the wire

 

[Hypocycloid3]

Pull your pillon seat and look from light backwards towards the front. A chaffed wire could be right at the main wiring point under the rear seat, the wires run right next to the frame there and the middle part that moves could have opened a bear spot in the wire

I actually did have a couple of crushed wires there. (I think that bundle has a group of 5) Cut 'em, stripped, reconnected, soldered and carefully covered with heat shrink ... thought I had the fix nailed down but no dice. Gotta keep looking I guess but hate to just keep unraveling everything. What 'likely' spot would you check next? Know of any tricks for testing exactly where the hot wire might be grounding out without tracing everything from one point to another?

 

[naughtyG]

Always check your bulbs too - they can short!

 

[Miles Long]

Was just hoping somebody has encountered this exact thing before so I can stop unraveling parts of my wiring harness looking for a short.

Whenever I use the break circuit, weather it's the hand break or the foot break... my headlight dims, no break lights, and if lever/pedal is held down for more then a few seconds... the second fuse,(first 10a) in line consistently blows. I thought the short was in the turn signal switch unit and replaced it. No change. Got new replacements for both stop light switches on order just for good measure because they have been though thousands of miles on my '94 anyway but I don't suspect that's where the problem is so any ideas are welcome. Thanks in advance.

Oh, forgot to mention... I can get turn signals and running lights, neutral indicator light etc. until either that fuse blows or as long as I have both break switches disconnected and leads taped off.

Where did you splice in the second fuse?
The same circuit causing you grief (the 10 amp one labeled "signal" at the fuse box), also feeds the turn signal relay and the horn. For starters, I would disconnect the horn and/or relay hot wires (both brown), and then turn the ignition on, and check the brakes. If they then work without blowing that second fuse, the problem is in one of those first mentioned feeds.
keep us posted. Cheers!

 

[DakRatFink]

I had a similar thing happen on my old FZR. Kept dead shorting on me and left me stranded at the least opportune times. Finally found a spot where a bundle of wires chafing on the frame. After re wrapping the wires in that spot, no more mysterious stalls.

 

[naughtyG]

I actually did have a couple of crushed wires there. (I think that bundle has a group of 5) Cut 'em, stripped, reconnected, soldered and carefully covered with heat shrink ... thought I had the fix nailed down but no dice. Gotta keep looking I guess but hate to just keep unraveling everything. What 'likely' spot would you check next? Know of any tricks for testing exactly where the hot wire might be grounding out without tracing everything from one point to another?

Under the seat there's a connector between the bike's main harness and the rear end's sub harness. Disconnect that (you will lose rear light, stop light and blinkers, maybe even fuel lamp I can't remember exactly) and then check your functionality. If you're not blowing any more fuses, then you'll know your problem is in this sub harness.

 

[Redbone]

When I was changing my turn signals a few years back I got the wiring wrong and kept blowing fuses when either testing turn signals OR applying the brakes. I hope you can sort this issue out quickly.

 

[Hypocycloid3]

Thanks for the ideas =) I should mention (NaughtyG) bulbs are good. Can get both running and break lights when i apply 12v directly to them. Also, it's probably worth mentioning that I have a set of stock, Vmax front turn signals (3 wire type) replacing the rear ones because I wanted additional break lights that can be seen better when I have luggage on for touring. So I have the third wire, tied to the breaking circuit using clear lenses and red bulbs. (which also makes my turn signals red but who cares) It's worked this way perfectly for years prior to this so reasonably sure I did that right. Thanks All! especially 'Miles' for ID'ing those brown wires, horn/turn signal relay. Thats just the kind of info and starting place I needed again. Will check it out! Please keep the suggestions coming ~

 

[Hypocycloid3]

MILES, I realized I did not answer your original question... The second fuse IS in fact the one labled "signal" at the fuse box. When you suggest to eliminate the brown horn and turn sig relay hot wires from the test equation..... do you mean pull them from the bottom of the fuse box or at the component itself?

Where did you splice in the second fuse?
The same circuit causing you grief (the 10 amp one labeled "signal" at the fuse box), also feeds the turn signal relay and the horn. For starters, I would disconnect the horn and/or relay hot wires (both brown), and then turn the ignition on, and check the brakes. If they then work without blowing that second fuse, the problem is in one of those first mentioned feeds.
keep us posted. Cheers!

 

[naughtyG]

Also, it's probably worth mentioning that I have a set of stock, Vmax front turn signals (3 wire type) replacing the rear ones because I wanted additional break lights that can be seen better when I have luggage on for touring. So I have the third wire, tied to the breaking circuit using clear lenses and red bulbs. (which also makes my turn signals red but who cares) It's worked this way perfectly for years prior to this so reasonably sure I did that right.

OK it's very possible that this is what happened: you wired correctly an extra load on a set of wires designed for a lesser load. Over years of use, some of these wires have been getting a bit hot (cos of the xtra load), their insulation weakened and eventually failed, causing the short.

I had a similar issue on an old car of mine - after it got broken into I replaced the ignition lock with a female stereo 1/4" jack socket and used speaker wire to connect it all. I had the only car ever using a 1/4" stereo headphones jack as an ignition key - very cool. But after a few months of use the wires' insulation melted and the whole thing went up in smoke very, very fast. Good job I got to the battery fast enough to disconnect before the car went up in flames, learned the value of having fuses everywhere that day lol..

Back to your problem though, you're gonna have to trace the power wire feeding the rear light + side markers, that's most prolly the one which melted itself or a neighboring wire. Then you need to replace that wire with a thicker gauge that can handle the added load created by 3 bulbs instead of one.

I still think it's most likely to be near a point of stress, and hopefully between that seat connector and the rear of the bike..

 

[Fitz666]

I had a similar issue and found out it was the rear brake switch which had been shorting out the whole circuit. A five minute swap over with a ?5 generic switch and it has been perfect ever since.

 

[Miles Long]

MILES, I realized I did not answer your original question... The second fuse IS in fact the one labled "signal" at the fuse box. When you suggest to eliminate the brown horn and turn sig relay hot wires from the test equation..... do you mean pull them from the bottom of the fuse box or at the component itself?[/QUOTE

I meant to just disconnect them at the components. This will take the turn signals and horn out of the equation , while still allowing power to reach the brake light circuit, and neutral light bulb. However..........
as Naughty just posted, the root cause of your problem may well be in the extra load put on the system, by the addition of the rear brake lights within the signals. The easiest check for this would be to disconnect the feed wire where it was originally spliced into the brake light circuit - If this wire(s) is shorting to ground, or the extra load is too much for the fuse, you will have eliminated both.
I have an extra tail/brake light on my bike, with two 1157 bulbs. I've never had a problem with overload. Maybe just good luck, other than good installation, don't really know.
As always, do the simple/inexpensive checks first. You will nail down the problem eventually. The "Process of Elimination" philosophy usually works.

 

[Hypocycloid3]

Got it! Thanks for all the help. It seems some of my mods were wired wrong to begin with even though it worked before changing the battery. I suppose the introduction of more 'juice' revealed an pre-exsisting problem in the break/signal/taillight circuit. Ripping all the tail end wiring out and starting over using a voltmeter and the manual (and most of the day) fixed it.

 

[naughtyG]

well done