Ignition fuse keeps blowing

[Yan]

Hello

Need help please.

Problem is intermittent.

Ignition fuse blown, but ONLY on initialisation, when I turn the kill switch on. If it doesn't get blown then, the bike will start and run just fine, and by run I mean run for 100 miles until I stop. Next time I start the bike it may or may not happen.

Happened a few times in the fall. Then this season I rode it some, including a 3 day long distance trip (during which the bike had gone through the start cycle at least half a dozen times each day) - no problem at all, until it happened again, out of the blue, this afternoon.

I realize there is a lot of stuff that gets powered by that fuse, but if it was a wire rubbing against the metal it would've inevitably be happening while I am riding. NEVER has it happened during a ride.

Can it be a bad relay? I am planning to order relays from the dealer and replace all four of them and see if that solves it.

What are you thoughts? Thank you!

 

[user_deleted]

Can it be a bad relay? I am planning to order relays from the dealer and replace all four of them and see if that solves it.

possibly. here's the test: REMOVE ignition relay from fusebox....install new correct amperage ignition fuse.....key switch off.....kill switch to off....now turn on key....now turn on kill switch. fuse ok? ignition relay is at fault. fuse still pops? dead short somewhere and can be a multitude of places.
where could it be? what relays cross over to factory relays and readily available on the cheap?
google "buell xb-lunaticfringe" and you'll see. have addressed this a ton of times on here including likely culprits, solutions and relay cross-over part numbers.
hints as follows:
fan headed to death row will pop both the fan and ignition fuse
faulty ignition switch. do the wiggle-key test.
chafed fuel pump feed wire
chafed wiring harness cluster at steering neck
chafed wire in harness under seat area
sub-harness running over and past right side muffler-to-cowling bracket chafed there.

 

[Yan]

Thank you, unfortunately the problem is intermittent, so I can pop the relay out, all good, pop it back in, still all good. For another week. Or a month.

I spent some time studying the wiring diagram for the Uly. It appears that a lot of things you mentioned aren't protected by the ignition fuse, but by various other fuses:

cooling fan has it's own fuse
key switch is on the key switch fuse
fuel pump is on the fuel pump fuse

a chafed wire anywhere on the bike would've been blowing the fuse when the bike is in motion as well (wouldn't it?), yet in never happened in many hours that it ran since it first happened in the fall until it happened again yesterday. It only happens when I flip the kill switch.

I can't think of anything but the relay, because it's the only thing where the electrical contacts are in motion when I flip the kill switch to ON.

am I missing anything?

Thank you again!

 

[Silverrider]

Trace your kill switch wires, in the switch and wires to and from .

 

[Yan]

Trace your kill switch wires, in the switch and wires to and from .

I looked at the wiring diagram, the hot wire that goes into the kill switch is protected by the Key Switch fuse, so if there was something fishy there that's the fuse that would've blown I guess...

 

[Silverrider]

http://buellmods.com/

 

[GregoXB]

I was intermittently blowing my 15 amp ignition fuse too. Sometimes it would blow instantly, other times I could ride it 20 miles and be fine. Turned out to be a frayed gray wire in my wiring harness, under my seat, shorting with another frayed black wire when the vibrations made them contact. https://www.buellxb.com/forum/showthread.php?54368-Blowing-15-Amp-ignition-fuse&p=600836#post600836

 

[Yan]

I was intermittently blowing my 15 amp ignition fuse too. Sometimes it would blow instantly, other times I could ride it 20 miles and be fine. Turned out to be a frayed gray wire in my wiring harness, under my seat, shorting with another frayed black wire when the vibrations made them contact. https://www.buellxb.com/forum/showthread.php?54368-Blowing-15-Amp-ignition-fuse&p=600836#post600836

View attachment 9885

Thanks! I am afraid the wiring is a bit different on my Ulysses (you have a Lightening, correct?). I was reading through your original thread - it started off when you were riding, and then it became worse and it would blow the fuse once you flip the kill switch, right?

 

[Yan]

http://buellmods.com/

great site, thanks for sharing! I already have the electrical manual though - is there more info there that could be useful?

thanks again!

 

[Silverrider]

Just keep a few fuses under the seat. and ride on safely.

 

[GregoXB]

Thanks! I am afraid the wiring is a bit different on my Ulysses (you have a Lightening, correct?). I was reading through your original thread - it started off when you were riding, and then it became worse and it would blow the fuse once you flip the kill switch, right?

Yes. It got to a point where I would flip the switch and it would instantly blow. I found the frayed wire under my seat, 2009 XB12Ss. The wiring on the Uly is different, trace the wires in the known problematic areas like Lunatic outlined. I narrowed mine down by getting a bunch of fuses and moving around sections of the wiring harness known to be problematic until the fuse stopped popping. Then I focused in on that section till I found it...

Note that if your fuel pump wires are chaffed, you will not be able to see that.

 

[Yan]

Just keep a few fuses under the seat. and ride on safely.

believe it or not, I went to the hardware store and bought a package of 25 15A fuses

I replaced all 4 relays with brand new OEM ones (turned out I had that many spare - my wife's Ulysses was having some starter relay issues and I stocked up on them at some point). Will see if that solves the problem...

thanks!

 

[Yan]

Yes. It got to a point where I would flip the switch and it would instantly blow. I found the frayed wire under my seat, 2009 XB12Ss. The wiring on the Uly is different, trace the wires in the known problematic areas like Lunatic outlined. I narrowed mine down by getting a bunch of fuses and moving around sections of the wiring harness known to be problematic until the fuse stopped popping. Then I focused in on that section till I found it...

Note that if your fuel pump wires are chaffed, you will not be able to see that.

Great, thanks a lot!

 

[user_deleted]

I spent some time studying the wiring diagram for the Uly. It appears that a lot of things you mentioned aren't protected by the ignition fuse, but by various other fuses:

cooling fan has it's own fuse
key switch is on the key switch fuse
fuel pump is on the fuel pump fuse

they in fact are "related" if you will. this is based on my dealings with this ignition fuse scenario for what seems like an eternity. though the fan and pump each have a dedicated fuse i'm telling you that a terminal fan will not only tend to pop its own fuse but the igntion fuse as well.....and same deal for the fuel pump. if its internal positive feed wire is chafed will do the same. they're always 2 of the first "problem children" i look at when dealing with this issue.

 

[Yan]

I spent some time studying the wiring diagram for the Uly. It appears that a lot of things you mentioned aren't protected by the ignition fuse, but by various other fuses:

cooling fan has it's own fuse
key switch is on the key switch fuse
fuel pump is on the fuel pump fuse

they in fact are "related" if you will. this is based on my dealings with this ignition fuse scenario for what seems like an eternity. though the fan and pump each have a dedicated fuse i'm telling you that a terminal fan will not only tend to pop its own fuse but the igntion fuse as well.....and same deal for the fuel pump. if its internal positive feed wire is chafed will do the same. they're always 2 of the first "problem children" i look at when dealing with this issue.

Thank you. Isn't the fact they multiple fuses get blown a sign of bad electrical design? Sigh

 

[TPEHAK]

It is.