Hi people

This is my first post. I am writing from Italy and have a 1979 FLH.
Right now I am building/restoring an almost stock 1976 FXE
Basically I got a basket full of parts (almost complete bike) + engine and frame. Bought and boughtOEM electrical harness from JPcycles. Now all the wiring is done. I turn ignition and all the lights fork, but have a little problem with brakes.
I have a stop swith like this (noy new or chromed, just old)
http://www.jpcycles.com/productdetai...rch=fxe%20stop
What I understand is that it's a push off switch. The brake pedal has a plate that pushes that pin in the middle. When I press the brake, the plate releasses the pin and stop light is supposed to glow.
Now what happens is: pedal is pressed, stop light glows. As soon as the plate touches the pin when brake is releassed, I can see sparks between both and stop light turns off (position light is still on). After a couple of seconds i hear a loud CLICK (1 of the 3 circuit breaker under the seat) and stop light turns on again. pressing and depressing the pedas makes nothing. After few more seconds circuit breaker works again, stop switch works but sparks are seen, and CLICK again.
What can the problem be? How does the stop ligt swith work? just pressing the pin? does it ground through the plate of the pedal?
Thanks

Giancarlo

 

Sounds like you've got a short in that switch, and it's grounding out.Or the wiring is flawed, and is grounding out somewhere when you activate the switch. In any case, the circuit breaker is doing its job by breaking the electrical current between the short before things get really overheated,and is saving it from frying your bike's wiring.Worst case would be starting a fire, which would add a whole different meaning to a hot bike! But definitely not the kind you'd want. I would toss that old switch in the trash, and get a new one. And double check your wiring to make sureit's wired up correctly andnothing else in the electrical wiring is shortingout. Replacing a $13 part is a lot cheaper than rebuilding a burnt out bike!

 

Yes,

What he said. Check and double check that wiring.

 

Thanks guys, will check both, the switch and the wiring. Maybe it grounds somewhere...

 

That stop light switch you have is for a mechanical brake setup, which I am assuming that's what you have. If you have a hydraulic brake setup, I would go with the hydraulic inline type brake switch. Most mechanical brake switches are wiredas constant hot, meaning that the wiring inside the switch is such that the circuit is closed at all times and is kept that way under/with a spring loaded device. In the case of your switch, the plunger (pin) is spring loaded to keep the switch closed until pressure is applied (pushed), which opens/breaks the electrical connection. The switch is usually installed with the plunger (pin) resting/pushing slightly against the brake pedal or hand lever just enough to break the electrical connection. When you push down on the brake pedal or pull the hand lever inwards, this takes pressure off of the switch's pin/plunger,which lets the spring loaded plunger come back in contact with the electrical connectors and closes the circuit. It's designed this way as a fail-safe device to take the guess work out of whether and when the brake light should work, if and when the brake pedal or hand lever is activated ever so slightly - when you press on the brake pedal or pull the hand lever inward slightly, the brake switch should activate your stop light without fail.

You can double check this by checking the switch’s continuity: Take an ohm or volt meter (if you use a voltmeter, you'll need a DC power source with a light bulb). Run one leadto one of the contacts, and the other lead to the other contact. When the pin/plunger is out completely (not pushed in), there should be continuity between the two contacts. When you push the pin/plunger in slightly, this shouldbreak the continuity/contacts.

Based on the above, the wiring should be: (important note: the switch does not use anything as ground, since the grounding source is taken atthe taillight/brake lightside ofthe setup) From the positiveside of thepower source (preferably from your ignition switch's on position - don't run this directly from the battery, and should bewith either a circuitbreaker, or fused, at 10 amps or less) to one of the switch's contact. Then from the switch's other contact, run a lead (wire) to the otherbrake light switch wiring (front or rear - wired up similarlybut so that either switch can/will operate the brake light), then run the final lead (wire) to your brake/tail lights – the tail/brake lights should have a ground wire, which of course grounds to your frame/fender). If you're not using the stock brake wiring leadsthat has the insulatedring terminals, make sure youuse an insulated ring terminalthat's the right size. Also make sure you use those little cardboard or plastic washers that came with the switch between the ring terminals and theterminal seats on the switch, and that nothing (bare wire or metal part of ring terminal) is touching and/or grounding out at or around the switch's connectors.

Best of luck and enjoy the ride.

 

WOW Shovel4ever..that's a lot of info!! And very useful!
anyway, problem solved, but not really know how. Actually before seeing the sparks betwenn the switch's pin and the brake pedal's plate, tha plate was in contact with the switch's built-in mounting bracket. While pressing the brake pedal, the plate was sliding right onto the bracket surfare..and there were also sparks. That meant the switch was grounding everywhere. After reading your first anssers I doublechecked all the wirings and they are OK. I took the switch off the bike and sprayed the inside with WD-40, pressing the pin a few times. Installed it back. It's not grounding anymore and works fine. Now the front brake swith doesn't work. I just need a new one I guess, because the stop light works when the 2 leads touch each other, but not once they are installed in the swith.
Anyway, thanks again!

G