so i posted a couple months  back about a carb problem, then i realized it was an electrical problem. and after failed diagnosis time after time, i replaced the harness

you would think that would be enough to get rid of an electrical problem

but its still here

So here's the deal, the bike only runs when i have either the front or the rear brake held in. So somehow, the bike isn't grounding well and has to use the front of the rear brake circuits as a ground. When i close those two circuits (put the connectors together) and ride around, i notice that the turn signals go crazy, blink blink blinkblinkblink blink. Everything other than that seems to work well when both brake circuits are closed

now when the circuits are open (there is no path to ground to whatever is the problem), then the bike stutters, wont go beyond 2k rpm. The console lights flicker.


I dont know what to do with this problem, i'm desperate really, havent ridden in 3 months because of this problem. I've gone to mechanics who dont have a clue, some electrical guy came up and was like (replace the harness), so i did, and no help.
ANY IDEAS are welcome, ANY.. seriously

Difficult........but after studying the diagram for a few minutes I would suspect the Diode pack.

a new diode came with the harness... new relays too, the only thing electrically that isn't from the new working harness is the ICU, rectifier, switches/coils/lights, controls and the starter relay

[edit] i took my multimeter down to the bike and checked on the diode pack, it seems to be functioning properly [/edit]

do you think there would be any long term side effects to the following

I would ground off the circuit containing the front brake/rear brake and disconnect the grounded circuit from any switches/lights

I would rig up an entirely new circuit for rear brake/tail light, which would be connected to the front and rear brake switches and the dimmer switch. I would ground out where the circuit usually grounds out, but i would be stealing power from the orange wire that would usually activate the passing lights in the 2002+ models


this is the orange wire im talking about, it leads to nowhere in the 02 and previous years, so i figure stealing that wire as my hotside wont be too bad.


my worries with this new wiring is that the wires which were my brake switches before are now acting as grounds which they weren't supposed to be before. I worry that they will become hot with the additional load, as they are pretty thing, probably around 18 gauge, and long paths for grounds for whatever isn't grounding in my bike

I have to give this some thought and it's bedtime, but it doesn't seem to be a grounding problem, as your front and rear brake switches don't ground anything, at least they're not supposed to!  My working theory is bolstered by the fact that your turn signals go berserk when you close both switches and ride the bike.  If it were a grounding problem, your problems would at that point be gone.  I'm assuming you have a US model like mine, 89-96.  Tell me your model year so I can make sure I'm looking at the right diagram.  Also, when you say it won't run, do you mean it won't start, or won't crank at all, i.e., dead?  Be as precise as you can with your descriptions so I can help you better.

Quote from: bill14224 on February 22, 2009, 10:59:46 PM
I have to give this some thought and it's bedtime, but it doesn't seem to be a grounding problem, as your front and rear brake switches don't ground anything, at least they're not supposed to!  My working theory is bolstered by the fact that your turn signals go berserk when you close both switches and ride the bike.  If it were a grounding problem, your problems would at that point be gone.  I'm assuming you have a US model like mine, 89-96.  Tell me your model year so I can make sure I'm looking at the right diagram.  Also, when you say it won't run, do you mean it won't start, or won't crank at all, i.e., dead?  Be as precise as you can with your descriptions so I can help you better.

[edit]what i mean by grounding is that whatever the phantom problem is, its using my brake circuit (through the brake wire, through the tail light, then dump to the neg battery) [/edit]


yeah, i have a 94 model. When i mean wouldn't run, i meant it ran like the pilot jet was almost completely clogged. It sounded as if the spark would miss every so often, or almost as if i were running on one cylinder at some points. to be even more clear, i'm going to take a video of it tomorrow after class when i'm wiring up the band-aid brake/tail light circuit. The cluster lights are dim when i dont have the brakes closed, and with every rotation of the motor, i can see it flickering. With everything closed up, it seems to run normally, except for the blinking turn signals. That, also, was very puzzling to me.

i'm going to finish the new circuit for the brake lights tomorrow, hopefully, as a temp fix, and hopefully resolve the real issue soon

What do you know?  I have a '94 too!  Now I can't sleep because I'm thinking about your problem..    Make sure all your connections to the regulator are good, including the ground to the battery, and the power connection through the fuse to the positive terminal of the battery, and we'll pick it up tomorrow.  All kinds of hell will happen if you don't have that. 

Now that I've had more time to think about this, there are several suspects on my list.  I'll go from easiest and most likely to hardest and least likely to try to save you some work.  The orange wire is not an "extra wire".  It is critically important to our bikes' proper operation.  It feeds power to your neutral and oil pressure indicators, brake lights, horn, and it also feeds the ignition coils through the sidestand relay.  It does quite a bit, and it's a switched power wire, meaning it's connected to the battery through the fuse whenever the ignition switch is on.  Leave your connections in their proper places for now.  If the ignition switch is failing, the power on the orange wire will be weak, causing the power to the ignition system and your indicators to be weak.  Spray a liberal amount of WD-40 into your ignition switch with the straw pushed inside, then work the key back and forth a bunch of times.  Then try to start the bike.  If that's not it, a poor connection to the ignition switch, or a poor connection to or inside the sidestand relay can cause the same thing.  I know this list is getting long, but these are the things that have to be eliminated one by one.  The next thing to do is remove the 4 wires from the ignition switch and connect them together, then start the bike.  Use alligator clips with wires on them to make the connections I instruct you to and make sure you don't let them touch the frame as they're all live wires!  If that's not it, remove the orange and orange/blue wires from the sidestand relay, connect them together, then start the bike.  I think we'll get it by then.  If not, I then want you to remove both connectors along the way between your regulator and battery and inspect for corroded pins, loose sockets, and/or connector pins or sockets that may have receded into the connector, causing a loose connection.  If it's a bad battery connection I'm gonna kill you!  Next, do the same for all connector pins and sockets between the regulator and alternator.  The pins and sockets lock in with little tabs cut into their sides.  Sometimes they can come loose, so you back it out the rest of the way, bend the locking tabs out a little more, then push it back into the connector until it locks in place.  Loose sockets can be fixed by using a jeweler's screwdriver to push the locking pins in, backing the socket out of the connector, squeezing the socket a little to make it fit tighter, bend the locking tabs out so they can lock again, then press it back into the connector until it locks.  Do these things carefully and methodically in this order, and I'm 99% sure you'll find the problem.  You can mail me 4 dozen homemade oatmeal raisin cookies!

We're going to get this puppy FIXED!  Three months is too long to go without your venerable GS 500, and 26 years as an electronic calibration and repair technician tells me this is the proper way to attack this problem.

Quote from: bill14224 on February 23, 2009, 04:05:16 PM
Now that I've had more time to think about this, there are several suspects on my list.  I'll go from easiest and most likely to hardest and least likely to try to save you some work.  The orange wire is not an "extra wire".  It is critically important to our bikes' proper operation.  It feeds power to your neutral and oil pressure indicators, brake lights, horn, and it also feeds the ignition coils through the sidestand relay.  It does quite a bit, and it's a switched power wire, meaning it's connected to the battery through the fuse whenever the ignition switch is on.  Leave your connections in their proper places for now.  If the ignition switch is failing, the power on the orange wire will be weak, causing the power to the ignition system and your indicators to be weak. 


Spray a liberal amount of WD-40 into your ignition switch with the straw pushed inside, then work the key back and forth a bunch of times.  Then try to start the bike. 


If that's not it, a poor connection to the ignition switch, or a poor connection to or inside the sidestand relay can cause the same thing. 


I know this list is getting long, but these are the things that have to be eliminated one by one.  The next thing to do is remove the 4 wires from the ignition switch and connect them together, then start the bike.  Use alligator clips with wires on them to make the connections I instruct you to and make sure you don't let them touch the frame as they're all live wires! 


If that's not it, remove the orange and orange/blue wires from the sidestand relay, connect them together, then start the bike.  I think we'll get it by then. 


If not, I then want you to remove both connectors along the way between your regulator and battery and inspect for corroded pins, loose sockets, and/or connector pins or sockets that may have receded into the connector, causing a loose connection. 


If it's a bad battery connection I'm gonna kill you! 


Next, do the same for all connector pins and sockets between the regulator and alternator.  The pins and sockets lock in with little tabs cut into their sides.  Sometimes they can come loose, so you back it out the rest of the way, bend the locking tabs out a little more, then push it back into the connector until it locks in place.  Loose sockets can be fixed by using a jeweler's screwdriver to push the locking pins in, backing the socket out of the connector, squeezing the socket a little to make it fit tighter, bend the locking tabs out so they can lock again, then press it back into the connector until it locks.  Do these things carefully and methodically in this order, and I'm 99% sure you'll find the problem.  You can mail me 4 dozen homemade oatmeal raisin cookies!

We're going to get this puppy FIXED!  Three months is too long to go without your venerable GS 500, and 26 years as an electronic calibration and repair technician tells me this is the proper way to attack this problem.

wow thanks so much, i just modified your quote a bit so i can tackle stuff one by one. this is going to be lots of work, i have a dead battery, so everytime i test anything i'm bump starting it. work for my young muscle. Today i tried grounding the orange wire, stupidly. It was only after the 3rd attempt at a push start that i realized that i had idiotically short circuited all the electricals on my bike. so i guess im going to fix this for reals, starting... tomorrow.. haha

and if and when i get this fixed, i am for sure mailing you a batch of my buddie's mom's secret recipe(she shared it with me) strawberry oatmeal cookies.

btw i couldn't get a vid of the bike, because parking enforcement threatened to give me a ticket if i didn't move immediately from the front of my dorm where i was soldering stuff together.

Save yourself a lot of work.  You have to charge your battery first, or buy a new one if it won't charge.  Don't charge it with more than 2 amps for 6 hours, or 6 amps for 2 hours.  Any longer than that and you'll roast it.  It's not a car battery.  Your bike has battery ignition.  It will run like crap unless it has a good battery in it.  Don't waste time with the video.  I have enough to go on, and don't do all the work at once.  Start with the ignition switch.  After the battery is charged or replaced, the ignition switch is my #1 suspect.  You'll probably have to replace the fuse first though, as you just blew it out today when you shorted out the orange wire!  With your weak/dead battery, maybe not.  You should have read my post first!  The more you tell me the more I'm thinking you have a bad battery and you're playing with wires you don't understand and that's the problem!

The GS 500 doesn't have a computer.  It is analog electronics with a few solid state components.  It is my specialty and profession.  Doubt or ignore anything I tell you at your peril! 

Now that you've had today's escapade, I want you to charge your battery, buy a new one if it won't charge, check your fuse, and put all the wires back where they belong, then shoot WD-40 in the ignition, work the key, then start the bike.  I'm 75% sure that will take care of it.  If not, follow my instructions in my previous post.  Do the steps one by one.  Start the bike after each step.  When you get it running good, you'll know what the problem was.  If you follow my instructions and don't go off on tangents you can't miss.

I'm with Bill on this one: you need to fix your problem rather than add a new brake light circuit. I'm also thinking that if you replaced the harness and you still have the problem, it exists in some component that you haven't yet replaced. Also, it seems like going through all the switches on the bike first would have been way easier than running a brand new harness through the bike. Not that you can change it now, but for the future, it usually is much better if you do all the easy stuff first.

Also, if parking enforcement is giving you grief, just take your bike into your dorm room...

Oh, and for all you folks out there who might read this.. when someone tells you that you need a new wiring harness, unless the bike caught fire there's a 99% chance the person telling you that is not competent to diagnose electrical circuit problems.  Find someone with an ELECTRONICS DEGREE FROM AN ACCREDITED COLLEGE, show him the schematic diagram, tell him your symptoms, and go from there.  I've seen so much bad advice concerning electrical problems here and everywhere else on the internet I want to tear my hair out!  Don't listen to heresay diagnoses, i.e. "my brother-in-law's bike had a similar problem and this is what he did", or "that orange wire coming off your ignition switch doesn't do much".  IT SURE AS HELL DOES.  The orange wire on the GS is as important as your aorta!

I remembered this kid from a few months ago, and after being jerked all over the place here he is with a bike that still won't run AFTER REPLACING THE WHOLE DAMN WIRING HARNESS AND HE'S RESORTED TO ARC WELDING WITH HIS IGNITION WIRE, so I had to step in.  I'm probably not the only person who reads these boards who could get to the bottom of this, but no one did, so I made it my priority to see to it that this kid gets the help he needs.  I'm not trying to piss in a circle and keep everyone else out.  All I'm saying is if you don't really understand circuitry, SHUT THE HELL UP!

And thanks for the props, Fred.

Sure thing Bill. I looked over the schematic and I think you're right: the ignition switch and side stand relay look like very likely candidates. I'm also a big fan of fixing the stock wiring rather than coming up with some random other solution. One of the first things I did when I got my bike was get rid of as much of the terrible wiring previous owners had done on my bike. I found totally crazy stuff like bare wire shoved into connectors and electrical taped in place, bad crimp connector splices and DIY frame grounds created by wrapping bare wire around the nearest bolt. Improvised electrical work might get you home if you're stranded, but it shouldn't be confused with a permanent solution.

some of that came out totally wrong, the electrical guys didn't actually tell me to replace the harness straight up. Each guy i worked with went about diagnosing the problem little by little with a multimeter. We couldn't get the bike running at that point, so we were diagnosing simply by having the ignition on and the bike wired to his battery. We found what we could explain none other than to be a short circuit, or a circuit that wasn't closing properly in the harness. I started tearing up the electric tape on the harness, jiggling it around and stuff to try and find the short. We examined most of the components on the bike, ironically, not the ignition or sidestand switch. After a total of about 7 hours he said that it would be less of a hassle if i just got a new harness, so i figured he was right.


buddha commented on my earlier thread say that 99% of electrical problems come from the connections, not the wiring. He's right, but i guess while me and my buddies were diagnosing, we just naively were searching in the wrong places

daliumong, Now that you've told me the bike was wired to a known good battery and the problem persisted, this is my list of suspects in order:

Put all your wires back where they belong, put a charged good battery in, check its connections, then turn the key on and check for lights.  If no lights, replace your fuse.
Then check:
1)  Ignition switch and connections to it
2)  The fat ground wire to the battery branches off into two wires, one grounding the regulator, and the other grounding the ignition contol unit, among other things.. CHECK THEM BOTH ALL THE WAY FROM THE REGULATOR AND I.C.U. ALL THE WAY TO THE BATTERY!
3)  Sidestand relay, and connections to it
4)  Regulator, and connections to it
5)  Based on what you're telling me, my top guesses are a weak connection to the orange wire from the ignition switch, or a weak ground on your ignition circuit caused by one leg of your grounding circuit I decribed above.  Either of those things will cause crappy ignition, and I'm fairly certain you have crappy ignition.  Now, put everything back where it belongs and tackle the problem, and no more arc welding! 

as soon as i got out of classwent to go buy a battery and wd40 and some oil for an oil change. So the battery says to fill it with acid and then charge it for 10 hours at 1 amp. the problem is, i only have a 2 amp charger. is this going to pose a problem? the charger is a smart charger, so it'll ease off the power once the battery reaches the correct voltage.

so i started doing number one of the check list right there, spraying wd40 in the ignition and going back and forth lots. no help there. tackle ignition and sidestand switch hopefully on thursday, by then i should have a fresh battery

Don't flunk out of school over your bike, but I'm glad you're getting started.  A new battery with new acid will already have a charge when you fill it, so I'm puzzled as to why they would want you to charge it at 1 amp overnight.  Perhaps to ensure it's fully charged.  You can use a new battery right away.  I've done it before in everything from bikes, to cars, to lawn tractors.  I didn't mention this before but you should also test your regulator while you're checking its connections.  It's not off my suspect list yet, but I'm glad the ignition switch is OK.. they're expensive to replace.

i think im pretty much going to take my manual out there tomorrow and test everything on the list, so i can find the current problem and perhaps deal with any future problems right now

and while making a jumper connector out of my old harness, i'm very scared and suprised as to how easy it would be to hotwire one of these bikes. just pop the two screws out of the headlight housing and stick a jumper in a connector... a person with any knowledge of a bike would be in and out in about a minute...

[edit]i just ordered myself a chain lock off of amazon[/edit]

I have a few more suggestions but eliminate the previous ones first to avoid confusion.