I was riding on the highway and my bike died as if I'd put the OFF/RUN switch in the OFF position. There were no other warning signs.

Now it's home and when I turn the key to the ON position, all electrical comes on and everything looks good as long as the OFF/RUN switch is in the OFF position. However, when I put the OFF/RUN switch in the RUN position, all lights dim and the circuit breaker under the seat starts to click. (I assume that it's being tripped.) As the circuit breaker trips and resets, all the lights will cycle back and forth from dim to bright. Also, a high pitched squeal that increases in pitch comes from the OFF/RUN switch for a few seconds while the circuit breaker continues it's trip/reset cycle. I also smell an electrical burning smell from the area under the seat.

Nothing happens when I press the Starter switch. It doesn't try to start in any way.

I have a 1988 Sportster 883. 21K Miles. Engine/Electrical are pretty stock. Hadn't ridden in about a year. Recently started riding back and forth to work, which is only a few miles from home. The day this issue started I was taking it on a 60 mile round trip and only got 5 miles down the road.

I was told by a MMI mechanic that it's probably a short in the wiring related to the OFF/RUN Switch. I am awful at tracing this kind of stuff. I've got a multi-meter, but not exactly sure how to go about diagnosing and eliminating variables in a logical way.

I've tried looking at other posts/threads on this and other sites, but can't seem to find anything that's similar to my issue. Any help would be great and much appreciated.

 

This sounds right. Do you have a service manual? The electrical diagrams in it are extremely helpful in this kind of situation. They also go in depth about continuity checks and a lot of other things. If you are planning on digging through the electricals, I would not do it without a schematic. (Service Manuals are about $50) Too much could go wrong. Good luck!

 

Thanks for the quick reply Scuba10jdl.

Yes I do have the service manual. I've looked over the wiring schematic and I believe that I understand it. I've also gone over the electrical troubleshooting guide though I struggle with that more.

I guess my issue is that I'm not sure how to go about determining where the short is. Is there a way to figure it out without tearing apart the places where multiple wires are bundled together?

I have a multi-meter but I'm not sure when I should be getting continuity and when I shouldn't.

Thanks for the help.

 

Well, I would start with the On/Off switch since that seems to be the issue. Trace the wires from there to the battery. You could check your fuses, and trace from the battery up to the switch. Unfortunately, that's why electrical work cost so much, lots of labor.

Either way, you're going to have to just check whether or not you have a hot wire where you are supposed to all the way up. If it's a short, it will quit somewhere along the line. You might try visually searching for a melted wire along the way, too. The smoke would indicate that. Just start tracing the wires up one at a time. It's a pain, but eventually you'll get it.

 

Thanks again for the quick reply.

As I sit here, I'm trying to think this through and break it down into sections.

The way I look at it, there are 4 possible components and the wiring between them that could be the problem. It starts at the battery and goes to the key switch. From there to the OFF/RUN switch. And from there to the circuit breaker that keeps tripping. One of those four components could be the problem. It could also be the wiring in between.

At this point, I do not believe it to be the battery or the key switch, nor the wiring between them. I could see the problem more likely being the wiring between the key switch and the OFF/RUN switch or the OFF/RUN switch itself. I could see it being the wiring between the OFF/RUN switch and the circuit breaker as well. The MMI mechanic said it's very unlikely to be the circuit breaker, but that's it always a possibility.

What does the START switch not functioning indicate? What must happen to let that function? Why would the START switch not function, but the OFF/RUN switch still send juice to the circuit breaker?

Why does the OFF/RUN switch squeal when I flip it to the RUN position?

Would a short in the wiring on the pre-side of the OFF/RUN switch still let it get electricity? Or when it shorts, would it be grounding out so that it didn't get electricity?

Obviously the OFF/RUN switch gets juice, or the circuit breaker wouldn't be tripping.

These are questions I'm asking for myself as much as anyone who reads this post. Hopefully if I'm on the wrong track, someone will let me know. I'll do what you said Scuba10jdl and try to systematically eliminate variables, starting with the OFF/RUN switch and working my way out from there.

Thanks again. Anyone else with ideas please post them too.