I have a 2005 sportster that had a battery go bad over the winter. I just got the replacement in the mail, one of those generic "pour these bottles of electrolyte in and charge before using" kind of things. A buddy of mine used a very high-end auto-charger for it after we poured the liquid and we really took our time with it.

Anyway, we put it on the bike and turned the key. The headlights/taillights come on. But the engine won't even attempt to turn over when you try to start it. No sound of a relay clicking or anything like that. Just dead silent when you try.

We took a look at this fuse box found just to the right of the battery under the seat behind the battery cover and found that even if the key was not in the bike, putting a new fuse into the socket would cause it to instantly blow. This is a little 15 amp, second down from the top closer to the little relay on the left. I've attached a picture showing where. My friend says there was another fuse found blown in the top just above it but that in the past it never affected the bike starting so he didn't know what it was supposed to go to. We also noticed that neither keyfob would enable or disable the alarm system (or at least no matter what you tried, the lights wouldn't blink in response to hitting or holding down the alarm button on the fob).

I have a service manual that I bought for around 30 bucks or so but it doesn't show the fuse box anywhere in it, nor really give an indication on the bike what that particular fuse goes to.

In the past I have had a problem with the speedometer, but not the odometer that seemed electrical but never cared to do anything about it. Just mentioning because it might be related.

Anyone know what this fuse goes to?

 

it is a battery fuse. Just take the spare from the bottom right to replace it.

 

here save this for reference.

 

The "Battery" fuse supplies power to the turn signal/security module, instruments, AND the Start button on the handlebar. Since the fuse blows again as soon as you replace it there is obviously a problem with one of the above or a short in the wiring that feeds them.

 

If it blows with all of the switches in the OFF position, I would trace the wiring from the fuse box and look for a spot that has rubbed against something or is pinched somewhere. If there is another fuse that does the same thing, chances are they both may be shorted at the same spot.

 

Thanks for your replies everybody. I will start by tracing the wiring from the box to try and find a short.

 

Shameless bump. I've got the same problem and need to pull the box to clean the wires coming in. Something is shorting out.

 

I have a similar problem. Keep blowing the neutral switch & speedo fuse. Pulled the neutral switch connector off and stll blowing fuses. I have not been able to locate a cut/frayed/problematic bare wire showing. wires have been in looms.

Advice?