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Discussion Starter #1
Ok, so I tried searching the boards for an answer and only kept digging myself a deeper hole. I am going to try and lay out everything I have done concisely so that the whole picture is clear.

1. Changed headlight to HID Xenon from Lumenez - everything worked fine
2. Changed brakelight to LED board from Moto Lume - everything worked fine

3. Installed LED Flasher Relay from Show Chrome Accessories - everything worked fine.
4. Changed front TS to LEDs from Custom Dynamics - everything worked fine
5. Changed rear TS to LED with running/brake lights from Custom Dynamics - blew a fuse after initial install, re-did all the wiring - everything worked fine.

6. Battery Died - did some testing, ruled out stator decided to change R/R to Shindeghan MOSFET--
charging DCV before change was 12.6-13.0 from idle - 6K RPM......After change was 12.7-13.5 same RPM range. This seemed strange to me so I had the battery tested and it was fine. So I figured perhaps I have a ground short somewhere. When I went to start looking for it, I noticed my headlight wasn't running. I looked up posts about that issue after the MOSFET install and noticed this

Headlight Not working after Install Thread...

I mostly paid attention to the posts by VulcanJoe and Denny as they seemed the most appropriate for me.

Post #7 seemed to be the answer, and if you read on to further posts it almost seems as though somehow my low charging voltage may have been related to this.

Post 7 reads
"i had the same problem when i installed mine so i wired it up like the factory with the stator lead to the jb then the r/r would not charge what i did was take the brown sense wire from the old r/r connector and solder it to the yellow wire from the small plug on the j/b. the headlight is on all the time now there is no longer a delay to turn on the headlight. hope this helps "

I misread this and tapped the Brown Sense wire into the yellow wire from the stator leading into the JB. Obviously, my headlight turned on (only after pushing start button), no other lights did, and in 30 seconds the main 30 amp fuse blew. I disconnected the wires I just put together to realize I just sent VAC voltage on the brown wire and it melted and shorted to the old ground wire in the no longer used R/R connector. So, I disconnected and fixed my cut. Now I am stumped, I do not see any other yellow wires coming from the JB other than the one from the stator. My headlight does not work at all, and I do not know where to attach the brown wire.

I think that this brown wire just needs to get 12V power to turn on the headlight, but I am not sure.

any help please

P.S. - I removed the White and Ground wires from the old R/R connector at the point where they join other wires because I wanted to clear up some space and get rid of the uneccessary wires.
 

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"i had the same problem when i installed mine so i wired it up like the factory with the stator lead to the jb then the r/r would not charge what i did was take the brown sense wire from the old r/r connector and solder it to the yellow wire from the small plug on the j/b. the headlight is on all the time now there is no longer a delay to turn on the headlight. hope this helps "
Very, VERY bad advice. As soon as the R/R turns on the FET of that phase, the FET shorts the battery. I'm afraid you have ruined your new R/R.

With the FH012AA, you leave the brown wire disconnected, just make sure it does not get shorted anywhere.
 

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Discussion Starter #3
Very, VERY bad advice. As soon as the R/R turns on the FET of that phase, the FET shorts the battery. I'm afraid you have ruined your new R/R.

With the FH012AA, you leave the brown wire disconnected, just make sure it does not get shorted anywhere.
I'm not sure I fully understand your post, but I'm pretty certain you are either misunderstanding my problem, or mistaken because...
after I took everything apart and examined the wiring diagrams and wiring harness, I soldered the stator wires directly to the R/R (removing the bullet connectors), still have the 1 stator wire split and going to the JB as it was stock, and have the red wire out of the R/R going to the battery and the black going to ground. The brown wire is disconnected as it was after I initially installed the new R/R

Long story short, everything is exactly as it was after R/R installation as per instructions. Battery charges between 12.6-13.5V depending on RPM so R/R is still working, but headlight still does not work at all. Since this brown wire is tied into the headlight circuit I assume the problem lies with this wire.

All other circuits work properly, and all fuses are good.
 

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Leave the brown wire alone. Insulate it and forget about it....
I believe most people just move the blue wire in the 8 pin connector of the JB to the empty pin next to it. (IIRC, pin 8 to 7). This solves the headlight problem.
 

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You may already know some of this, but let me try to explain some things. The only wires that need to go to the new R/R is the stator wires and the two new wires that come with the kit for the battery. When I replaced my stator I used the original yellow wires on the bike because of the one that went to the JB. The WHT/R wire you can cut at the R/R connector and tape it off or use a heat shrink cap if you can find them, this wire is the positive lead from the R/R which you replace with a new one from the Mosfet to the battery. Your original battery wire stays in place and the Mosfet positive wire gets is added to the positive lead of the battery. The WHT/R wire being cut at the R/R doesnt matter because it is spliced elseware in the harness and is still connected to the battery. Pretty much the same thing for the BLK ground wire. The BRN wire like you mentioned is the sensing wire. IT IS NO LONGER NEEDED FOR THE MOSFET. What this wire did was take output of the R/R via the WHT/R wire through the ignition switch and feed it back to the R/R. I guess the original R/R needed to know what it was putting out. So this wire gets cut and stowed also. The yellow stator wire that goes to the JB operates the headlight relay, this is how the headlight works only when the bike is running. Basicly when you tied the yellow and the BRN wire together you took the output of the R/R 12-14 VDC and connected it to the output of the stator 50-70 VAC. OUCH !!!!! So there is a good chance you fried something. I would check continuity of the stator wires, maybe even check the output while the bike is running just to be sure your stator is good. You can find several post on how to check the stator. Hook up the Mosfet correctly. Then check the output of the mosfet, I get almost 14 VDC at idle, If the input to the mosfet is good (stator voltage) and the output is bad I would say you damaged the Mosfet. THAT IS IF YOU DIDNT FRY ANYTHING ELSE. Personally I left the headlight circuit alone, so it would operate as designed, not moving the blue wire, There will not be a headlight issue when the mosfet is installed correctly. When my headlight went out it was the only indication I had that there was a problem (bad stator). You mentioned removing the WHT/R and the BLK wires completly from the bike to where they spliced, I guess it would be ok as long as you didnt disturb the actual splice or respliced the wires after removing the unneeded ones. Hope this helps you understand whats going on. Here is a link of how I installed my mosfet.

http://www.vn750.com/forum/showthread.php?t=18361&highlight=mosfet
 

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Discussion Starter #6
You may already know some of this, but let me try to explain some things. The only wires that need to go to the new R/R is the stator wires and the two new wires that come with the kit for the battery. When I replaced my stator I used the original yellow wires on the bike because of the one that went to the JB. The WHT/R wire you can cut at the R/R connector and tape it off or use a heat shrink cap if you can find them, this wire is the positive lead from the R/R which you replace with a new one from the Mosfet to the battery. Your original battery wire stays in place and the Mosfet positive wire gets is added to the positive lead of the battery. The WHT/R wire being cut at the R/R doesnt matter because it is spliced elseware in the harness and is still connected to the battery. Pretty much the same thing for the BLK ground wire. The BRN wire like you mentioned is the sensing wire. IT IS NO LONGER NEEDED FOR THE MOSFET. What this wire did was take output of the R/R via the WHT/R wire through the ignition switch and feed it back to the R/R. I guess the original R/R needed to know what it was putting out. So this wire gets cut and stowed also. The yellow stator wire that goes to the JB operates the headlight relay, this is how the headlight works only when the bike is running. Basicly when you tied the yellow and the BRN wire together you took the output of the R/R 12-14 VDC and connected it to the output of the stator 50-70 VAC. OUCH !!!!! So there is a good chance you fried something. I would check continuity of the stator wires, maybe even check the output while the bike is running just to be sure your stator is good. You can find several post on how to check the stator. Hook up the Mosfet correctly. Then check the output of the mosfet, I get almost 14 VDC at idle, If the input to the mosfet is good (stator voltage) and the output is bad I would say you damaged the Mosfet. THAT IS IF YOU DIDNT FRY ANYTHING ELSE. Personally I left the headlight circuit alone, so it would operate as designed, not moving the blue wire, There will not be a headlight issue when the mosfet is installed correctly. When my headlight went out it was the only indication I had that there was a problem (bad stator). You mentioned removing the WHT/R and the BLK wires completly from the bike to where they spliced, I guess it would be ok as long as you didnt disturb the actual splice or respliced the wires after removing the unneeded ones. Hope this helps you understand whats going on. Here is a link of how I installed my mosfet.

http://www.vn750.com/forum/showthread.php?t=18361&highlight=mosfet

Ok, That's the thing. I followed your instructions to the T. The only reason I tired connecting the brown wire to the yellow wire was because my headlight wasn't working.

Also my voltage across the battery was low before I attached the brown wire also.

After putting everything back together all voltages/resistance measurments at all locations are exactly the same as they were before I connected things.

The reason I do not think I fried anything, is I don;t think I actually turned the engine over, I just hit the starter button real quick to make sure the headlight turned on. I was not running the engine. So I am not entirely sure why the wire got so hot and melted through the casing and grounded itself out..

Either way, my headlight does work when it gets power. This I am sure of, but with everything installed exactly the way you did it, the headlight does not work.

I hope this explains a little bit better why I am so confused...:confused:
 

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Discussion Starter #7
Leave the brown wire alone. Insulate it and forget about it....
I believe most people just move the blue wire in the 8 pin connector of the JB to the empty pin next to it. (IIRC, pin 8 to 7). This solves the headlight problem.

Thanks, that is what I needed to know.
 

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Just breaking the large block of information in the previous post into bite sized pieces that I can digest. :) Thanks for the clear explanation of the mosfet mod on the Vulcan ifixf18s. :smiley_th
You may already know some of this, but let me try to explain some things.

The only wires that need to go to the new R/R is the stator wires and the two new wires that come with the kit for the battery.

When I replaced my stator I used the original yellow wires on the bike because of the one that went to the JB.

The WHT/R wire you can cut at the R/R connector and tape it off or use a heat shrink cap if you can find them, this wire is the positive lead from the R/R which you replace with a new one from the Mosfet to the battery.

Your original battery wire stays in place and the Mosfet positive wire gets is added to the positive lead of the battery. The WHT/R wire being cut at the R/R doesnt matter because it is spliced elseware in the harness and is still connected to the battery.

Pretty much the same thing for the BLK ground wire.

The BRN wire like you mentioned is the sensing wire. IT IS NO LONGER NEEDED FOR THE MOSFET. What this wire did was take output of the R/R via the WHT/R wire through the ignition switch and feed it back to the R/R. I guess the original R/R needed to know what it was putting out. So this wire gets cut and stowed also.

The yellow stator wire that goes to the JB operates the headlight relay, this is how the headlight works only when the bike is running. Basicly when you tied the yellow and the BRN wire together you took the output of the R/R 12-14 VDC and connected it to the output of the stator 50-70 VAC. OUCH !!!!! So there is a good chance you fried something.

I would check continuity of the stator wires, maybe even check the output while the bike is running just to be sure your stator is good. You can find several post on how to check the stator.

Hook up the Mosfet correctly. Then check the output of the mosfet, I get almost 14 VDC at idle, If the input to the mosfet is good (stator voltage) and the output is bad I would say you damaged the Mosfet. THAT IS IF YOU DIDNT FRY ANYTHING ELSE.

Personally I left the headlight circuit alone, so it would operate as designed, not moving the blue wire, There will not be a headlight issue when the mosfet is installed correctly. When my headlight went out it was the only indication I had that there was a problem (bad stator).

You mentioned removing the WHT/R and the BLK wires completly from the bike to where they spliced, I guess it would be ok as long as you didnt disturb the actual splice or respliced the wires after removing the unneeded ones. Hope this helps you understand whats going on. Here is a link of how I installed my mosfet.

http://www.vn750.com/forum/showthread.php?t=18361&highlight=mosfet
 

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Can we do a sticky of this? Or an entry in the verses?
 

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Perhaps an image will help you understand what I am saying:



You connected the brown wire from the ignition switch to the yellow wire from the JB. The engine did not have to start running, just turn fast enough for the stator to output enough voltage for the R/R to trigger the FET (probably the instant you released the start button).

This created a path for the current to flow from the positive battery terminal to the negative battery terminal (the dashed red path in the image).

Since FETs keep on conducting until the current drops to zero, the current kept flowing until the main fuse blew. There is a good chance that the FET failed and shorted out. You can test with a resistance meter if any of the AC inputs of the R/R is shorted to the R/R ground wire. If you are lucky, there was enough resistance in the wires to limit the current so that only the fuse blew and no other damage was done.
 

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Discussion Starter #11 (Edited)
Perhaps an image will help you understand what I am saying:



You connected the brown wire from the ignition switch to the yellow wire from the JB. The engine did not have to start running, just turn fast enough for the stator to output enough voltage for the R/R to trigger the FET (probably the instant you released the start button).

This created a path for the current to flow from the positive battery terminal to the negative battery terminal (the dashed red path in the image).

Since FETs keep on conducting until the current drops to zero, the current kept flowing until the main fuse blew. There is a good chance that the FET failed and shorted out. You can test with a resistance meter if any of the AC inputs of the R/R is shorted to the R/R ground wire. If you are lucky, there was enough resistance in the wires to limit the current so that only the fuse blew and no other damage was done.

So what am I looking for to see if R/R is bad. Test all 3 AC inputs to Ground output and hopefully I see infinity or OL and not a resistance reading?

Also if the R/R was bad, wouldn't I expect to see absolutely no voltage change at battery terminals with engine running? I am still seeing the exact same readings I was seeing before I created the short.
 

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Since FETs keep on conducting until the current drops to zero..
Sorry, my bad. FETs don't conduct until zero current. Thyristors do. But then why did the fuse blow? Perhaps there are thyristors in the control circuit of the FETs..

Anyway, test the AC inputs to ground both ways (reverse the probes). If you see near zero ohms both ways then something is absolutely wrong. Also, the readings from the AC inputs to the output or ground should show about the same readings - both ways again.

If only one phase of the R/R is bad, you could still get a reduced output.
 

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Discussion Starter #13
Everything seems ok.?.

Except still puzzled by the low output and headlight not working, gonna try to do some more tests tonight when I get home from work.

I chanced it and rode to work today, no problems at all on the 25 mile ride. She still runs like a champ
 

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Discussion Starter #15
You stated:

"I soldered the stator wires directly to the R/R (removing the bullet connectors), still have the 1 stator wire split and going to the JB as it was stock,"

By soldering the stator wires directly to the RR; bypassing the bullets, how do you power the headlight relay needed to run the headlight? Isn't it after the bullet connectors/before the RR connector where a sole stator wire tee's off to the JB (that powers relay only when the bike is running)? You do state that you still have a stator wire going to the JB, but is it powered?; how?

Keeping in mind that you "soldered" stator directly to RR, did you also solder (tee off) one of those stator wires to the JB in order to power the headlight relay?

Also, I'm looking at the wiring diagram of the manual; that brown wire connects/branches off to a lot of things that run off DC: horns/guages/lights/switches/etc... You literally put AC current through all of this; for 30 seconds!... (something to keep in mind)... Ride safe.
I simply moved the T to a different location on the same stator wire. Yes, it still goes to the JB and def has power. (Actually what I did was cut the wires on both side near the bullet connections and soldered the ends together. I still use a connector at the R/R

Yes, I am aware of what a bonehead move I made. Still trying to figure out how I made that mistake. Bottom-Line is I have had so much success taking advice from this board that I didn't read the wiring diagram first or even trace the wires. Furthermore everytime I re-read that passage I got the info from, I still infer the same thing.

Either way, I am keeping a close watch on everything that may have been affected. To be quite honest I am completely surprised that everything is in working order. Perhaps it wasn't quite 30 seconds, it may have only been 2-5 seconds for that matter, but still long enough to do damage. I will chalk it up to good luck. Perhaps pay back on the Karma I earned by giving out some free parts to those in need. :smiley_th

So does anyone have any ideas other than moving the blue-white wire over to the empty pin location to help remedy my headlight situation.
In fact, can anyone verify that this is safe to do. Guess I learned you can never be too careful.
 

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Discussion Starter #16
Ok, after re-reading the entire thread linked in th OP this is what I conclude.

I do need to connect the brown wire to the yellow wire in the JB.

BUT!!!!! First I need to disconnect that yellow wire from the one leg of the stator. Thereby bypassing the headlight relay. That is where my mistake was, and I simply read the first post by vulcanJoe wrong.

Any input here please

Also could this be a problem in the J/B not fuse related? What is going on inside the J/B? Or could this be a problem with my reserve lighting device not working properly if all the wires are connected properly?
 

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Please tell me your not thinking about hooking up that BRN wire to the yellow wire again. You need to cap that wire tape it up and forget about it. When you turn your ignition switch on your going to apply 12 VDC from the battery on that wire. Do you have a set of schematics ? If not there is a maintenance manual you can download for free. Here is a link to the post when my headling stopped working, JD put a link there for a manual. Its a PDF file so you need acrobat reader and its about 112M. Im assuming you checked the stator output and did the resistance checks, However you did mention that you road to work and back. So it sounds like the stator is working. You could start the bike and check for the 50-70 VAC at the yellow wire on the R/R plug to make sure thats its good, Maybe you damaged the headlight relay when you hooked up 12VDC to it when you connected the yellow and BRN wires together. On my headlight post it mentions about moving the blue wire, it worked for me, then I found out I had a bad stator. After repairing the stator I moved the blue wire back to its original place.


http://www.vn750.com/forum/showthread.php?t=17610&highlight=headlight
 

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Discussion Starter #19
lol, ok, I will just move the blue wire,

Thanks for the fast and very definitive responses.
 

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Discussion Starter #20
Ok, so maybe this is obvious, but why is there a leg of the stator going into the JB anyway?

As far as I can tell, nothing at all on the bike needs AC voltage, so why the yellow wire going to there in the first place? And is there any harm to removing it? I amnot actually considering doing this, I will simply move the blue wire now, and replace the stator in the off season if it makes it till then, but I am just trying to understand the wiring on this bike
 
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