headlight problem just got worse - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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Where does this wire go?
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post #1 of 18 (permalink) Old 03-25-2011, 07:07 PM Thread Starter
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headlight problem just got worse

started out with a headlight not working, someone replied to check the charging system. Well batt voltage is under 12VDC with the engine running and slowly declines. checked the voltage on the yellow wire of the 10P connector of the junction box and it was less then 2 VDC. So i think i have an alternator problem. Does someone have a link for the charging system schematic? If it is the alternator is it something that can just be replaced?
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post #2 of 18 (permalink) Old 03-25-2011, 09:12 PM
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not a charging problem.. not yet.. you have a JB problem.. search headlight problem.. good write ups on moveing the headlight wire to an empty slot in the sonector on the Jb/fuse box.
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post #3 of 18 (permalink) Old 03-26-2011, 11:34 PM
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I had to look back at your other two threads to get a bead on this, but...

If the bike's starting and running OK without running down the battery, you've either got a junction box problem or a bad connection elsewhere, and it sounds like junction box. However, charging under 12 volts at the battery and slowly dropping sounds like stator (alternator) or regulator/rectifier, or both, unless I'm missing something here. Both times I lost the headlight, it was the stator. And yeah, it's something that can just be replaced--right after you pull the engine.

You need to buy a manual, or download one here:

http://www.tocmanufacturing.com/Products.htm

Scroll down the page, and under Other Links, it says "Link to VN700/750 Service Manual in PDF format (WARNING 117MEG file) click here"; right click on "here", and save to a file on your hard drive. It's a *.pdf file. There's seperate diagrams for each part of the electrical system in the electrical section, and a complete schematic, along with a parts catalog section for each year.

If ya can fix a Hornet, ya can fix a Vulcan; read and study the manual, run the checks on the stator and R/R, and the junction box.

J.D.
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post #4 of 18 (permalink) Old 03-27-2011, 02:15 AM
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I have to agree with J.D. I was on a ride a t a rally, and the guy in front of me slowed down and said "hey, you know your headlight is out??" WTF??!! I pulled the bulb and it was fine. Rode it home and got up the next day and tried to figure it out, I couldnt. Come to find out, my stator was bad. If you notice, when you get on your bike and turn the key on, the headliglight does not come on. This is so your battery can devote all its power to starting the motor. What triggers the light to come on is a certain amount of voltage/amperage coming from the Stator. Your headlight suddenly stops working? I will bet it is your stator.
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post #5 of 18 (permalink) Old 03-27-2011, 09:01 AM
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Quote:
Originally Posted by 94vn750FL View Post
\ If you notice, when you get on your bike and turn the key on, the headliglight does not come on. This is so your battery can devote all its power to starting the motor. What triggers the light to come on is a certain amount of voltage/amperage coming from the Stator.
No, the headlight should power up when the key is turned to the 'on' position. It does cut off while the starter is engaged however.
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post #6 of 18 (permalink) Old 03-27-2011, 06:05 PM
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Headlight FIX

All. first time posting here, this forum is great. I've searched around and found some references to the "blue wire fix" which was going to be my last resort.

My headlight too did not work. Last year, I futzed around with wires, checked headlight, didn't find anything wrong, and viola, it started working again, ugh. Stayed working until the end of the year.

This year, I put on new tires, lubed my drive shaft, got it all back together, and bam, no headlight again. Ok, something other than a stupid connector is to blame. I started digging, doing diode checks and relay checks on the junction box. Having been bit by the junction box BS once before (fan relay wouldn't engage, causing overheating, causing blown battery, ALMOST causing stator, but luckily for me, stator was fine).

Don't be afraid of that junction box, it is a piece of cake. Unscrew it, unplug the two connectors and take it out. Now my bike is a 1994, and the JB has 4 melted posts that hold it together. I simply drilled them out and then popped it right open (take out all the fuses first though). The pictures below shows what I did. The first time I got bit, the ribs on the back of the JB rubbed away circuit board traces!!!!! I had to solder in new wires to replace the lost traces and shave down the offending ribs with a knife. Fan problem solved.

This time was a bit more evil. Checking the diodes from the connector, sometimes one would work, sometimes not. UGH. checking the diodes right on the board, perfect every time. Wierd. COLD SOLDER JOINT!!!!! I found that on pin 15, where it connects to the circuit board, if i looked real close, there was a crack in the solder! Lucky to find it! I simply resoldererd every connection point where each connecter connected to the circuit board, snapped it back together, remounted it, and HEADLIGHT FIXED!!!!

I guess after 17 years, that junction box gets its share of wear and tear, but the insides are grade school electronics, not much in there to fail, other than the circuit board itself!!!! I'm uploading pictures, next post will show what I mean. Bottom line, tear into the junction box, it is pretty simple.

EDIT: reading KM60155 in the last post..... The headlight only comes on after the first time you push the start button (at least on my '94). It stays on if you turn off the bike. It turns out if you try to restart the bike, while the starter is pushed in. So, first time you turn on your key, light is NOT on. After you start, light on. If you turn your run switch off, light still on.

Last edited by prijo; 03-27-2011 at 06:42 PM.
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post #7 of 18 (permalink) Old 03-27-2011, 06:31 PM
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Headlight Fix with JB Pictures

ok, here are the promised pics.

Ok, the first pic shows the JB and where it is mounted on the bike (side of battery cage) (you'll see some stuff you don't recognize, like inline 20 amp fuses on the stator leads, everyone by now has moved their regulator to the outside of the bike )

Second picture shows how I fixed the traces by soldering a copper wire across the broken traces

Third picture shows the inside of the JB and the scraped down ribs.
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post #8 of 18 (permalink) Old 03-27-2011, 06:58 PM
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If I understand correctly, you said the volts drop while it is running, testing at the battery with a volt meter. Lets forget the headlight for a minute. The system has to charge for it to come on at start up.

I bounced this headlight out problem around on here for several days. Check the stator just one time this way. Undo the wire plug at the Regulator, check each lead to the stator (yellow wires) one at a time to ground using a voltometer, checking ohms to ground. If the meter ohms out, stator is ground. 27 year Kawasaki mechanic told me this was most always the case. Was on my bike. Test the same way on a good one it will not show ground. The head light has to have power from a charging system to turn on (Diode in the JB) but will stay on if the engine is cut off with the thumb kill switch on the handlebar. As far as the JB, you can bypass the jb by removing the power lead at the R/R plug and run a wire in it's place straight to the battery and that cuts out everything except the stator, the r/r, and the battery. You can test your voltage at the battery while the engine is running. Also, If you are getting 2vdc on the 12v lead at the R/R while the engine is running that is a hint that it is going to a ground, somewhere.

Got my old stator and a new one in my hand with a voltmeter as I type. Could be just the R/R. If the stator is out, I would replace the R/R also.

Last edited by Chuck A.; 03-27-2011 at 08:14 PM.
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post #9 of 18 (permalink) Old 03-27-2011, 07:08 PM
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Quote:
Quote:
EDIT: reading KM60155 in the last post..... The headlight only comes on after the first time you push the start button (at least on my '94). It stays on if you turn off the bike. It turns out if you try to restart the bike, while the starter is pushed in. So, first time you turn on your key, light is NOT on. After you start, light on. If you turn your run switch off, light still on.
only if you use the handlebar mounted switch does the head light stay on.if you turn the key off it goes out immediately and does not come on until the engine actually rotates enough for the stator to supply voltage to the light relay in the JB.




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post #10 of 18 (permalink) Old 03-27-2011, 08:50 PM Thread Starter
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OK, This is what i found. I downloaded the PDF Manual as suggested by JD. According to the manual i checked the voltage at the battery with the engine is running. Less then 12 volts and voltage declined as the engine was running, I turned the brights of the headlight on and the voltage dropped even more (I moved the blue wire earlier). So i did the resistance checks of the stator at the R/R connector. None of the wires were shorted to Ground. However checking resistance between the wires was not good. Whenever a meter lead was on the center wire the meter read an OPEN. Resistance between the outer wires the reading was 10 OHMS. The manual says it should be .3 to .5 ohms. Seems i have a defective stator. Do i really need to remove the motor?
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