Brake switches blowing fuses

[Guest]

After doing some work on the bike today I went for a ride and noticed I had no turn signals, and the gear indicator/dash cluster was dead. I cut the ride short and went back home to check further. The brake lights were also dead. Not the tail light, just the brake light. Checked the fuses and indeed there was a blown one.

I replaced it and everything seemed good till I hit the front brakes. The fuse blew again. I put another fuse in and this time checked the rear brake pedal. Fuse blew again, I replaced it again. This time I switched through the gears, used the turn signals and everything was fine. So the brake light system seems to be the issues.

I went and checked the wiring diagram for my bike and noticed that both the brake switches are on a wire (the white wire) that nothing else from that fuse connects to. Now I totally admit to being a novice with electrical repair. So my question is should that be where I start my search for a short?

And the work that was done included

• Replacing a bad chain tensioner gasket
• Installing larger main jets
• Installing new boots on the airbox
• Removing some play in the clutch cable
• Installing a headlight visor

[cowboyup3371]

Have you gone through the harness to see if the shielding might have worn through anywhere? It sounds like a bare wire is touching something it shouldn't.

[MechMessiah]

Have you gone through the harness to see if the shielding might have worn through anywhere? It sounds like a bare wire is touching something it shouldn't.

No, it was too dark out to get a good look at the harness. I'm trying to gather info for working on it tomorrow.

[BigD_83]

It does sound like it is a wire common to both the rear and front brake, so I think your hunch is correct.

Of course, there is a possibility that you have two problems, but keep it simple to start.

[dorkburger]

Looks like it's fused thru the yellow / green. That looks to provide power to both the front and rear brake switches, among other things. Since the problem is common to both switches, I'd start at the brake light and start tracing the wires back to look for damage. May be good to check the bulb socket as well.

[MechMessiah]

Thanks for the suggestions. I've got my multimeter and I've watched a few youtube videos on finding shorts. I'm really hoping to find this quick, and be an easy fix. I hate chasing electrical gremlins.

[Steve]

I replaced it and everything seemed good till I hit the front brakes. The fuse blew again. I put another fuse in and this time checked the rear brake pedal. Fuse blew again, I replaced it again. This time I switched through the gears, used the turn signals and everything was fine. So the brake light system seems to be the issues. ... So my question is should that be where I start my search for a short?

It appears that you have answered your own questions.
Since everything works until you use the brakes, follow that white wire that goes from the front brake switch all the way to the brake light, and picks up the rear switch along the way. You will have to take the tank off to check the harness there, as well.

One of the prime suspect areas is where the harness leaves the headlight bucket and rubs on the side of the steering neck. It moves and drags on the neck every time you use the bars, so it would be rather easy to wear through the insulation at that point. There are two bullet connectors inside the headlight bucket. One feeds the front switch, the other one goes from the switch to the light. Start there, follow it through the maze in the bucket, past the steering neck, along the frame rails under the tank to the battery area, where the wire from the rear switch will join it. Continue on to the brake light. Check the wires under the seat to make sure the seat has not pinched the wires. Finally, check the wires inside the light housing.

Looks like it's fused thru the yellow / green. That looks to provide power to both the front and rear brake switches, among other things.

Huh? The only yellow/green wire on the bike goes from the starter button to the starter solenoid. Not even on the same fuse.

Now, if you were talking about ORANGE/green, I could believe you, as that is the fuse that feeds all the signals, including turn signals, brakes, horns and warning lights.

.

[dorkburger]

Steve, I stand corrected. The O / G was the one I was referring to though.

[Redman]

Grn/Org wire to front & rear brake switch (as others have said).
Wht wire from front & rear brake swtich to brake light (as you said).
Follow the Wht wire as much as you can.
Look under the seat, near the back.

Disconnect the wht wire from each brake switch, and see if still blows fuse, slight chance could be shorting out inside the switch.
Plug those back in. Remove the brake light bulb, see if still blows fuse. Is rare that the bulb shorts out, but can happen.
I would suspect the bulb socket more than the bulb, so look at that too.



.

[MechMessiah]

Thanks for all the advice, it was very helpful as I got it fixed. I found two spots that were a little suspicious. The first was under the seat where some of the shielding has been worn through. There was no obvious break or exposed wire but there were pressure indents on them where a stray metal bit could have been poking into the wire. I wrapped the questionable wires with electrical tape before I rewrapped the whole bundle.



The second spot is where the wires connect to the front brake switch. This seemed like the more legitimate location to be causing the blown fuse. I've got it wrapped with electrical tape for the time being but I'm going to replace the switch/wiring just to be safe.



I also checked several of the connections with a multimeter and test light just to be sure. Every test yielded positive results so I'm good to ride again. Alright not quite. Still need to figure out this carb tuning cluster ... but that's a post for another topic.

[Rijko]

good job you solved it.




Can it be the wires under the seat should go between metal bracket and inner fender ?
As it is now the seat will probably push the wires onto the edge of the bracket causing it to bite into the insulation.
Maybe someone with a 650 can help out on the cable routing.

[Redman]

................... The first was under the seat where some of the shielding has been worn through. There was no obvious break or exposed wire but there were pressure indents on them where a stray metal bit could have been poking into the wire. I wrapped the questionable wires with electrical tape before I rewrapped the whole bundle..
.
.
..

And... would one of those be the white wire....?

The one at the brake switch would definatly be the brake light circuit.

Good progress.

From pics I suspect that is the L .

.

[MechMessiah]

And... would one of those be the white wire....?

I can't remember if the white wire was but the ground was the roughest looking of the bunch.

From pics I suspect that is the L .

This isn't the L, just the standard 650 shafty. My L is completely disassembled and slowly going through a full rebuild and upgrade.

[cowboyup3371]

good job you solved it.




Can it be the wires under the seat should go between metal bracket and inner fender ?
As it is now the seat will probably push the wires onto the edge of the bracket causing it to bite into the insulation.
Maybe someone with a 650 can help out on the cable routing.

Good eye; yes, the wiring should get routed under that brace if it is one and not just an indentation

[habsdoc]

I don't think that is a brace. I think it is molded to allow the fender parts to mesh onto one another.