Bonneville America Forums Forums Technical Forums General Tech Short - blown fuse

Hi all,

I have a 2006 America. I am having trouble with a short/blown fuse. The fuse is the one for the signal light, brake lights and horn. First the mods. I installed an aftermarket horn (I think from newbonneville), under engine in front of rear wheel, as well as front signal relocation to forks.

I first had the problem a couple of years ago but I found that I had lost a bolt from the muffler, the one that I had used to ground the horn. I replaced the bolt and the problem went away. Unfortunately it is back. I checked the muffler bolt and the horn is still grounded.

What happens:
When I replace the fuse the signal lights will work and the horn will work. As soon as I touch either front or rear brakes the fuse blows.

Any help appreciated.

Sounds like your turn signals are wired backwards and are grounding out on the forks. I had the this happen with K&S turn signals from British Customs. They had two wires, a black wire and a black with a white a stripe. Turns out the black with white stripe is the ground on most aftermarket turn signals. I naturally assumed the black was. Swapped them around and was good to go.

Oh, and as far as the horn goes, I replaced mine with a horn from the newer Thunderbird models, it is much louder and beefier sounding. I got it from the dealership for a comparable price to the aftermarket ones and it is a direct plug and play swap. Also, if you are using aftermarket turn signals that use anything higher than a 10w bulb, you will either need to swap out the bulbs to 10w or swap out the turn signal relay for a higher capacity one like this https://www.amazon.com/gp/product/B008C9YJ6C/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

Did you remove the lamp for the tail light? If the signals and horn work and using the brakes blows the fuse...

Thanks guys. I'll check out these tips and update when I find the problem.

Cool, let us know what you find for sure.

I had the same problem with my 07 Speedmaster blowing fuses when I used the rear brake. Check the wiring harness for chaffing where the top frame splits under the seat. I have a Freak kit and the bracket had worn into the harness shorting out the brake wire

Maybe check the rear brakelight actuator?

Ah, better details this time. When ridden was it the front or rear brake that blew the fuse? Because I'm guessing a chafed wire in the headlight bucket...

The wiring harness to the brake light was wedged very tightly between the frame and the fender just behind the battery. I free the cable. There doesn't seem to be damage to the harness but the fuse didn't blow. I haven't have a chance for a test ride yet but hoping for the best.


As for front or rear, both will blow the fuse. I had initially thought it was the headlight bucket as well but couldn't see any chafed wire. I don't even see chafing on the brakelight harness. If it is just a pinched wire it I don't know if I will find it. I may just have to replace harnesses until the fuses stop blowing.

You have accomplished the hard part, you have the problem narrowed down. I had a simular problem on an old Chevy Biscayne and after much hair pulling, it turned out to be the rear 1157 bulb itself. The filament had broken loose and rewelded itself into a dead short when the brakes were applied, within the glass bulb.

The worst part of this is that the problem is intermittent. Plus expensive in blown fuses. what I really need is a 10 amp circuit breaker I can insert into the bike. Anyone know if this exists?

I stripped the bike down today. I started with the rear harness. With the rear harness off things initially looked good, but no, just intermittent. I have ruled out the rear harness.

Based upon the wiring diagram the problem must between the front break or rear break and the connection to rear harness under seat. Green and purple wire. #9 on front brake connector, #2 on connection to rear manifold (connects to blue wire).

I took off the tank and opened up the headlight bucket. I could not see an issue. I put the headlight back together and things looked promising. No blown fuse. That was until I put the gas tank back on. Dang?

At this time I also came across another intermittent issue. The right signal light relay would buzz went signal activated. I switched the right and left leads and the problem is in the harness to the right handle grip. I visually inspected and could not see a problem. I will probably replace this harness at the very least. (at least this is an easy replacement).

I tested the brake wires from under the seat to the connector in the headlight bucket with a multi meter and there was a connection with no battery attached to the bike. I'm not the an expert with the multi meter but I did see a signal. I also tested the brake wire with ground and didn't see any current. I don't know if this is the intermittent nature of wrong wire. I also preformed the same test on the right signal wires and again the wire seemed to connect without grounding.

I am now pretty sure the problem is somewhere between the front break lever and the main harness where in goes under the tank. I'm going to stop at the dealers and see about getting a right harness and see if that fixes the problems.


Still open to suggestions. Maybe its time to get a new bike. I have had my eye on the Explorer for a number of years now.

PinWall in Ohio has reasonably priced harnesses.