Strange Electrical Problem . . . Solved Again

**tomm** · 08-07-2022, 11:16 PM

Did you ever wonder how the Nomad can have a 42 amp alternator and only a 30 amp main fuse? Or why some folks seem to have these charging problems that all the part swapping in the world or contact cleaning doesn't seem to fix?

So back some time, I had this charging problem that drove me crazy for several months, but finally found the culprit to be a crimp connector buried in the main wiring harness. Bypassed it and problem fixed . . . right? Well yes, but not permanently!!! Problem came back last month. Charging system seems to work fine at idle, but not as revs increase. See thread on first go-around with this problem. http://www.vulcanbagger.com/forums/s...ad.php?t=49990

Well, essentially the same problem this time as last, just a different crimp connector, but buried deeper in the wiring harness than the other one. Both crimp connectors are on the white wire, which connects the battery, the alternator, the junction box and the ignition switch together. It is 16 gauge, is always energized, and it carries a lot of current. The main fuse is between the battery and the other three items. And both times, my problem was a crimp connector over-heating.

I decided to write up what I found to fix this second problem because I think a lot of us, including me, are stressing these two crimp connectors without realizing it as we've added accessories to our bikes, and setting ourselves up for some electrical gremlins which are very difficult to find and fix. Below are some important points to understand.

1) The battery connects to the junction box and feeds a white wire through the 30 amp main fuse.
2) The white wire feeds the junction box and a number of fuses located within it.
3) The white wire also feeds the ignition switch directly. It is always energized.
4) When the ignition switch is turned on, the white wire feeds a brown wire which feeds the remaining fuses in the junction box and other assorted circuitry on the bike, and also a grey wire which feeds the computer.
5) CRITICAL POINT: The alternator connects to the white wire between the junction box and the ignition switch somewhere in the main wiring harness through one of the crimp connectors. Current from the alternator goes directly to the junction box and the ignition switch without going through a separate fuse.
6) In the stock configuration, the only current going from the alternator to the battery is through the main fuse and is whatever is required to charge the battery. And the only current going from the battery to the white wire through the main fuse is whatever is required to supplement current from the alternator at idle, usually hardly anything. So a little current left to right, a little current right to left, and net current through the main fuse is minimal.
7) CRITICAL POINT: Hooking up an auxiliary fuse box, accessory lighting, heated clothing, or any other accessory directly to the battery is supplied by the alternator only by current going through the main fuse from the white wire to the battery. This can seriously overload that white wire, or more precisely, crimp connectors on that white wire.
7) CRITICAL POINT: There are two crimp connectors located deep within the wiring harness where the white wire connects to the ignition switch and alternator, the junction box on the bike side of the main fuse, and the battery through the main fuse. Over time, these crimp connectors WILL overheat and break down, especially if accessories are added to the bike fed directly from the battery. When this happens, and depending on exactly how they break down, there will be a bad connection(s) between the alternator output, the ignition switch, the battery and the junction box. The symptoms of this will appear to be bad rotors, bad stators, bad ignition coils, bad rectifier / regulators, bad ignition switch, poor connections to the battery, poor grounds, and who knows what else. These crimp connectors are carrying a lot of current, potentially up to the maximum that the charging system is capable of putting out (spec'ed at 42 amps). The wattage being dissipated in the crimp connectors will be the current through them squared, up to roughly 1750, times the resistance of them, which should be zero. So even a very tiny resistance could generate some really significant heat.

We've learned that the connections underneath the left side cover between the stator outputs and the rectifiers can develop some resistance and get very hot, often burning up, and sometimes taking the rectifiers and/or the stators with them. So we've also learned that it is best to solder those connections because those two alternators combined can put out up to 42 amps. What's never been obvious however is that all that current feeds a 16 gauge wire through a couple of crimp connectors, and as we add accessories to our bikes we are increasing the current through those connectors. In order to avoid over-stressing the electrical system on our bikes we often add an auxiliary fuse panel connected directly to the battery, or relays connected directed to the battery, to power additional lighting, air horns, heated seats / clothing, etc. What we haven't always remembered however is that the bike essentially runs on the alternator output, not the battery. The battery is primarily used to start the bike, smooth out the alternator output, and to supplement the alternator at idle. And what we haven't realized is that in order for the alternator to power all those additional accessories connected to the battery, the current has to come to the battery via the white wire and those two crimp connectors through the 30 amp main fuse. So the alternator is powering the bike via the white wire directly to the ignition switch, and powering the accessories via the white wire through the 30 amp fuse to the battery and to the accessories from there. The alternator can put out 42 amps without blowing the 30 amp main fuse because the only current that is going through it is whatever the battery needs to stay charged, and whatever the accessories that we've connected directly to the battery require. But again, all that current, current going to the bike through the ignition switch, current going to the junction box, and current going to the battery and connected accessories through the 30 amp main fuse is going through those crimp connectors and a 16 gauge wire that should carry no more than 10 amps.

Fix is actually pretty simple. Bypass it all. Run a wire from the alternator output and splice it into the white wire at the ignition switch. Run a second wire from the alternator to the white wire coming up from the alternator above the crimp connector, bypassing that crimp connector buried in the wiring harness. And lastly, run a third wire from the alternator directly to the battery through a 30 amp fuse and 12 gauge wire, bypassing the other crimp connector in the main harness and forcing the voltage on all three legs of the white wire along with the battery to be the same (regulated alternator output voltage). (Note that this puts the 30 amp main fuse and 30 amp fuse being added in parallel. This is not ideal, but only alternative is to either replace the wiring harness or unwrap it to find those crimp connectors and replace them with soldered connections and heavier wire. But having the two fuses in parallel is probably not a problem because almost everything on the bike is fused separately and a direct short will blow both fuses anyway.) Be aware that this works if you've replaced your regulator / rectifiers with ones that have an internal regulator connection. If you have the original regulator / rectifiers with an external regulator lead, the regulator lead needs to be connected to the brown wire coming off the ignition switch. Make sure that with the ignition switch on, the voltage on the white wire going into the ignition switch is the same as the voltage on the brown wire coming out of the ignition switch, and the same as the voltage on the brown wire feeding the regulator. If not, replace or disassemble and clean the ignition switch and possibly also bypass the brown wire.

Finally, just to make sure the fix has been implemented correctly, with the bike running, check the voltage at the battery, at the alternator output, on the white wire at the ignition switch, on the brown wire at the ignition switch, on the brown wire at the regulators (if applicable) and on the white and brown wires at the junction box. They should all be exactly the same, both at idle and when revving the engine. The voltage at idle will probably be about 13 volts, and between about 13.9 and 14.5 when revved. If this is not what you find, then you still have a bad connection somewhere and/or another problem.

Note that there are many threads showing as an example how to add accessory lighting to a Nomad using a relay triggered by the wiring to the headlight and powered from the battery. I actually added quite a few accessories in this manner. In my last go-around with this problem before I finally figured out what was going on, the plastic of my main fuse was actually melted, although the fuse wasn't blown. There was over a volt difference between the end of the white wire at the ignition switch where I had connected the alternator output, and at the battery. Same wire in theory. Indicative of the current flowing through that crimp connector and the resistance of it.

This is not an easy problem to wrap one's head around if you are experiencing the associated symptoms and none of the typical fixes take care of it. It seems that adding accessories to a Nomad isn't as straight-forward as it would seem to be. And I have never seen another thread referencing this issue. There is another alternative fix however, which I was reminded of by another member of the forum . . . sell the bike.

DragonLady58 · 08-08-2022, 04:24 PM

Great WriteUp Tomm!!!!! Straight forward, easy to understand! With this little writeup, you can probably say with certainly that you've pulled several people bacon outta the fire with this....
Usually it takes a few years to get in depth into a wiring harness like this, believe you me, i've split several Nomad looms apart digging for the problem crimps, often just loping out the bad section, soldering in a new piece, heat shrinking the fix....
All this said, these bikes are still out there, you can find them pretty cheap, they are a extremely good deal!
Now, since these bikes are older, they are a good buy....even with all the negatives, which, if taken care of, you'll probably never experience them....
I absolutely HATED electrical problems at the dealership....I'd rather teardown a complete engine instead of screwing around in the wiring harness....
Several guys hit me up swapping jobs like that....
That changed about 15 years ago, with my Nomad, I just said screw it, I'm gonna fix this shit....after my plugs melted (under the left hand side cover) on the side of the road, in the winter, heading to NYC...., from Atlanta....

Anyway, My Hats off to you Tomm! Cudos! Again, Great Writeup!

08-07-2022, 11:16 PM	#1
tomm Join Date: Sep 2008 Location: Lee, New Hampshire Posts: 568	Strange Electrical Problem . . . Solved Again Did you ever wonder how the Nomad can have a 42 amp alternator and only a 30 amp main fuse? Or why some folks seem to have these charging problems that all the part swapping in the world or contact cleaning doesn't seem to fix? So back some time, I had this charging problem that drove me crazy for several months, but finally found the culprit to be a crimp connector buried in the main wiring harness. Bypassed it and problem fixed . . . right? Well yes, but not permanently!!! Problem came back last month. Charging system seems to work fine at idle, but not as revs increase. See thread on first go-around with this problem. http://www.vulcanbagger.com/forums/s...ad.php?t=49990 Well, essentially the same problem this time as last, just a different crimp connector, but buried deeper in the wiring harness than the other one. Both crimp connectors are on the white wire, which connects the battery, the alternator, the junction box and the ignition switch together. It is 16 gauge, is always energized, and it carries a lot of current. The main fuse is between the battery and the other three items. And both times, my problem was a crimp connector over-heating. I decided to write up what I found to fix this second problem because I think a lot of us, including me, are stressing these two crimp connectors without realizing it as we've added accessories to our bikes, and setting ourselves up for some electrical gremlins which are very difficult to find and fix. Below are some important points to understand. 1) The battery connects to the junction box and feeds a white wire through the 30 amp main fuse. 2) The white wire feeds the junction box and a number of fuses located within it. 3) The white wire also feeds the ignition switch directly. It is always energized. 4) When the ignition switch is turned on, the white wire feeds a brown wire which feeds the remaining fuses in the junction box and other assorted circuitry on the bike, and also a grey wire which feeds the computer. 5) CRITICAL POINT: The alternator connects to the white wire between the junction box and the ignition switch somewhere in the main wiring harness through one of the crimp connectors. Current from the alternator goes directly to the junction box and the ignition switch without going through a separate fuse. 6) In the stock configuration, the only current going from the alternator to the battery is through the main fuse and is whatever is required to charge the battery. And the only current going from the battery to the white wire through the main fuse is whatever is required to supplement current from the alternator at idle, usually hardly anything. So a little current left to right, a little current right to left, and net current through the main fuse is minimal. 7) CRITICAL POINT: Hooking up an auxiliary fuse box, accessory lighting, heated clothing, or any other accessory directly to the battery is supplied by the alternator only by current going through the main fuse from the white wire to the battery. This can seriously overload that white wire, or more precisely, crimp connectors on that white wire. 7) CRITICAL POINT: There are two crimp connectors located deep within the wiring harness where the white wire connects to the ignition switch and alternator, the junction box on the bike side of the main fuse, and the battery through the main fuse. Over time, these crimp connectors WILL overheat and break down, especially if accessories are added to the bike fed directly from the battery. When this happens, and depending on exactly how they break down, there will be a bad connection(s) between the alternator output, the ignition switch, the battery and the junction box. The symptoms of this will appear to be bad rotors, bad stators, bad ignition coils, bad rectifier / regulators, bad ignition switch, poor connections to the battery, poor grounds, and who knows what else. These crimp connectors are carrying a lot of current, potentially up to the maximum that the charging system is capable of putting out (spec'ed at 42 amps). The wattage being dissipated in the crimp connectors will be the current through them squared, up to roughly 1750, times the resistance of them, which should be zero. So even a very tiny resistance could generate some really significant heat. We've learned that the connections underneath the left side cover between the stator outputs and the rectifiers can develop some resistance and get very hot, often burning up, and sometimes taking the rectifiers and/or the stators with them. So we've also learned that it is best to solder those connections because those two alternators combined can put out up to 42 amps. What's never been obvious however is that all that current feeds a 16 gauge wire through a couple of crimp connectors, and as we add accessories to our bikes we are increasing the current through those connectors. In order to avoid over-stressing the electrical system on our bikes we often add an auxiliary fuse panel connected directly to the battery, or relays connected directed to the battery, to power additional lighting, air horns, heated seats / clothing, etc. What we haven't always remembered however is that the bike essentially runs on the alternator output, not the battery. The battery is primarily used to start the bike, smooth out the alternator output, and to supplement the alternator at idle. And what we haven't realized is that in order for the alternator to power all those additional accessories connected to the battery, the current has to come to the battery via the white wire and those two crimp connectors through the 30 amp main fuse. So the alternator is powering the bike via the white wire directly to the ignition switch, and powering the accessories via the white wire through the 30 amp fuse to the battery and to the accessories from there. The alternator can put out 42 amps without blowing the 30 amp main fuse because the only current that is going through it is whatever the battery needs to stay charged, and whatever the accessories that we've connected directly to the battery require. But again, all that current, current going to the bike through the ignition switch, current going to the junction box, and current going to the battery and connected accessories through the 30 amp main fuse is going through those crimp connectors and a 16 gauge wire that should carry no more than 10 amps. Fix is actually pretty simple. Bypass it all. Run a wire from the alternator output and splice it into the white wire at the ignition switch. Run a second wire from the alternator to the white wire coming up from the alternator above the crimp connector, bypassing that crimp connector buried in the wiring harness. And lastly, run a third wire from the alternator directly to the battery through a 30 amp fuse and 12 gauge wire, bypassing the other crimp connector in the main harness and forcing the voltage on all three legs of the white wire along with the battery to be the same (regulated alternator output voltage). (Note that this puts the 30 amp main fuse and 30 amp fuse being added in parallel. This is not ideal, but only alternative is to either replace the wiring harness or unwrap it to find those crimp connectors and replace them with soldered connections and heavier wire. But having the two fuses in parallel is probably not a problem because almost everything on the bike is fused separately and a direct short will blow both fuses anyway.) Be aware that this works if you've replaced your regulator / rectifiers with ones that have an internal regulator connection. If you have the original regulator / rectifiers with an external regulator lead, the regulator lead needs to be connected to the brown wire coming off the ignition switch. Make sure that with the ignition switch on, the voltage on the white wire going into the ignition switch is the same as the voltage on the brown wire coming out of the ignition switch, and the same as the voltage on the brown wire feeding the regulator. If not, replace or disassemble and clean the ignition switch and possibly also bypass the brown wire. Finally, just to make sure the fix has been implemented correctly, with the bike running, check the voltage at the battery, at the alternator output, on the white wire at the ignition switch, on the brown wire at the ignition switch, on the brown wire at the regulators (if applicable) and on the white and brown wires at the junction box. They should all be exactly the same, both at idle and when revving the engine. The voltage at idle will probably be about 13 volts, and between about 13.9 and 14.5 when revved. If this is not what you find, then you still have a bad connection somewhere and/or another problem. Note that there are many threads showing as an example how to add accessory lighting to a Nomad using a relay triggered by the wiring to the headlight and powered from the battery. I actually added quite a few accessories in this manner. In my last go-around with this problem before I finally figured out what was going on, the plastic of my main fuse was actually melted, although the fuse wasn't blown. There was over a volt difference between the end of the white wire at the ignition switch where I had connected the alternator output, and at the battery. Same wire in theory. Indicative of the current flowing through that crimp connector and the resistance of it. This is not an easy problem to wrap one's head around if you are experiencing the associated symptoms and none of the typical fixes take care of it. It seems that adding accessories to a Nomad isn't as straight-forward as it would seem to be. And I have never seen another thread referencing this issue. There is another alternative fix however, which I was reminded of by another member of the forum . . . sell the bike. __________________ Tom Maziarz (tomm) VBA #00766 2008 Kawasaki Nomad (Black) 1978 Suzuki GS750EC (My son is riding it now.) 2017: National Rally - Lake George, NY 2016: NE US / E Canada Rally - Mont Tremblant, QC 2015: National Rally - Eureka Springs, AR 2014: NE US / E Canada Rally - Lincoln, NH 2012: NE US / E Canada Rally - Wellsboro, PA Login or Register to Remove Ads
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08-08-2022, 04:24 PM	#2
DragonLady58 Sr. Member Join Date: Jul 2016 Location: Somewhere South of Alaska.... Posts: 2,351	Great WriteUp Tomm!!!!! Straight forward, easy to understand! With this little writeup, you can probably say with certainly that you've pulled several people bacon outta the fire with this.... Usually it takes a few years to get in depth into a wiring harness like this, believe you me, i've split several Nomad looms apart digging for the problem crimps, often just loping out the bad section, soldering in a new piece, heat shrinking the fix.... All this said, these bikes are still out there, you can find them pretty cheap, they are a extremely good deal! Now, since these bikes are older, they are a good buy....even with all the negatives, which, if taken care of, you'll probably never experience them.... I absolutely HATED electrical problems at the dealership....I'd rather teardown a complete engine instead of screwing around in the wiring harness.... Several guys hit me up swapping jobs like that.... That changed about 15 years ago, with my Nomad, I just said screw it, I'm gonna fix this shit....after my plugs melted (under the left hand side cover) on the side of the road, in the winter, heading to NYC...., from Atlanta.... Anyway, My Hats off to you Tomm! Cudos! Again, Great Writeup! __________________ --------------------- Don't start no schit, there won't be no schit.... My Sarcasm is directly proportional to the amount of Stupidity involved --------------------- VBA#03239 VROC#37400 VRA --------------------- 2014 Vaquero 2001 Nomad FI 2003 Street Glide (sold) 1500 Meanie, fresh rebuild (sold) 90s BUBF Bobber (sold) 2001 UltraCycle FatPounder (Sold) 1975 HD ElectraGlide (Sold) 1982 Kawasaki Z1 Chopper (Sold) Suck It Up & Ride!
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