fuse blows when either brake switch applied

[Kamisue]

I rebuilt my front calipers and bled the brakes - 100% ok

However, activating either brake will blow the fuse for the brake lights/turnsignals/horn.

I've tried it with the front switch unplugged, the bulb removed and it still blows the fuse.

the front switch is ok per the manual, open when no brakes and closed when brake lever is applied.

Can anyone point me to places where I can start isolating and checking to see where the short has occured?  I have a wiring diagram with the shop manual but my eyes aren't real good anymore for following those tiny lines.

It looks to me like the wires from the front switch go into the start switch housing and then leave that housing down into the wiring harness.  Can I unplug that somewhere to isolate?

The only place I did any work at all was on the front brakes and I did spill a little brake fluid but I had a towel wrapped around the master cylnder.  could I have shorted something out inside the handlebar switch housing? 

Everything was functional before I rebuilt the calipers.  It's one of those electrical gremlins that crept in during the bad cold snowy weather and I was waiting on parts for the calipers.

Any idea as to where to start looking would be helpful.  I almost know what I'm doing with a multimeter.  Thanks.

[Chrisj CMA]

The wires from the start switch housing go directly into the headlight.  follow the wire bundle and you will find a black square plug with a single blue and white wire off to the side.  that is all the controls from the right handlebar

PS this is for a standard or tourer....I dont know how the Interstate is wired, probably not the same

[Kamisue]

I should have said this is a 98 tourer - thanks

[Challenger]

I think I would remove the seat and RH side cover, disconnect the wire coming through the rear fender under the seat to the connector under the side cover for the rear lights and retry. this is a lot easier to eliminate that portion of the circuit first. If it still blows the fuse then you will have some tracing to do. Do you have any add on lights or cruise control? 

[Kamisue]

I have the turn signal modification from electrical connection.(extra brake and running lights)

I've already unplugged that.  Thanks for the input. 

I'd like to isolate each section like you suggested.

[Thunderbolt]

that will eliminate the brake light assembly in one shot.

[Madmike]

Remove taillight bulb so that there is no connection through the bulb filament to ground.

If you replace the fuse and it is ok until you apply either of the brake controls then the problem is most likely after either of the switches as power is supplied to both switches and they are open and closing either of them allows power through the switch to the bulb.  There  should be the Green wire with the yellow tracer - if you look under the seat there should be a 5 pin connector (with blue, gr/yl, gr, br and or wires in it) split this connector and see if you still blow the fuse when you apply the brake if you do then the short to ground is in the green/yl wire somewhere in the frame back to one of the switches.  If the fuse holds then then the ground is in the green/yl wire somewhere between the 5 pin and the taillight.

Alternatively you could split the connector and with your multimeter check the gr/yl wire each side of the 5 pin to ground and see where you have continuity.

Don't apply power to the circuit or you could fry your OHM meter.

[alph]

you obviously have a short.  take the bolb out, check out if there is anything shorting your circuit to ground, with out the bulb in, put in a fuse and see if it blows, you might have something shorting out your switch also.  there's not much to the whole break circuit.  if you don't have a meter, get a bunch of fuses.  NEVER EVER use a larger fuse, the fuse is there to protect your wire from melting!

[Kamisue]

ok, just an update - it's raining so I'm slow getting going.

I disconnected everything at the 5 pin connector and the fuse holds. 

That helps because now I know the problem is in the rear section of the wiring instead of up by the switches where I had been looking.

so I intend to concentrate on the gr/y wire back to the tail light assembly since I'm assuming that it the hot wire. 

Thanks for the assistance so far. 

[Daniel Meyer]

That helps because now I know the problem is in the rear section of the wiring instead of up by the switches where I had been looking.

Look under the fender...it's not uncommon to scrape/damage the wires there.

Next, there is a connector between the removable rear-fender segment and the main fender that can get pinched if not handled correctly.

[fudgie]

That helps because now I know the problem is in the rear section of the wiring instead of up by the switches where I had been looking.

Look under the fender...it's not uncommon to scrape/damage the wires there.

Next, there is a connector between the removable rear-fender segment and the main fender that can get pinched if not handled correctly.

+1 on what Daniel said.  Thats where mine shorted out. It was 6 years or so since that portion was messed with. But thats where it was.

[Kamisue]

well, I have brake lights and running lights and turn signals again.

The problem was self induced 2 years ago when I installed the electrical connection running/stop lights that modify the turn signals.

I spliced the connections under the fender so when time came to remove the rear section of fender I could just unplug those wires along with the regular wiring harness.  Maybe when I sat on the bike after the brake work my splice work gave way.  I'll never know why it failed.  It worked great for 2 years.  And then it didn't.

To make a long story short I just removed that modification and put the lights on the rear back to stock and everything works fine again.  I always figured a rock or something kicked up by the rear tire might damage the extra 4 wires and the splice but I did my best to get everything tied up out of the way.  Just wasn't meant to last.

Thanks to everybody for the suggestions.  Isolating the issue was the key to deciding what to do.

Just so the problem wasn't a total waste of time I hacked off those cages for the square fender nuts while I had the rear fender section off.

[RoboCop]

 I have a wiring diagram with the shop manual but my eyes aren't real good anymore for following those tiny lines.
 .

Same problem here.  I colorized (mostly) a schematic that's easier to read, about 20Mb.  You can download it from here:

http://www.mediafire.com/imageview.php?quickkey=b1rjnkwmzwm&thumb=6

.

[Bone]

Thanks for the file.

[RP#62]

 I have a wiring diagram with the shop manual but my eyes aren't real good anymore for following those tiny lines.
 .

Same problem here.  I colorized (mostly) a schematic that's easier to read, about 20Mb.  You can download it from here:

http://www.mediafire.com/imageview.php?quickkey=b1rjnkwmzwm&thumb=6

.

I just redrew them altogether.  Couldn't follow the factory schematics.
-RP

http://www.rattlebars.com/valkfaq/schematics/