Alternator wiring sanity check MkIII

After initial 20 mile run after rebuild bike quits. Found low battery charge and alternator wires shorted (my mistake).

Followed diagnostics posted here and found alternator still has continuity and is not grounded on either end of coil.

Wiring diagram says there should be green/white and green/ yellow coming from alternator but I have two green/yellow with two green/yellow and one green/white coming from rectifier.

1. Have I damaged the alternator by running it shorted?

2. Do the green/white and green/ yellow pair on one side?

3. Assume polarity does not matter...?

The fettling fun continues!

Andy --

ag12680 said:

Wiring diagram says there should be green/white and green/ yellow coming from alternator

Click to expand...

Those wires should actually be white/green [WG] and green/yellow [GY] (green/white [GW] is the RH indicator/blinker circuit)

ag12680 said:

two green/yellow and one green/white coming from rectifier.

Click to expand...

One harness GY should go to the Edit: rectifier and then to the zener, the other GY goes to the assimilator, similarly, there should be two WG wires? One going to the rectifier and 2nd Zener, the other WG to the assimilator, therefore you appear to have a missing WG harness wire?.

ag12680 said:

1. Have I damaged the alternator by running it shorted?

Click to expand...

Possibly not.

ag12680 said:

2. Do the green/white and green/ yellow pair on one side?

Click to expand...

Normally, the stator WG would connect to the two harness WG wires, and the stator GY to the two harness GY wires.

ag12680 said:

3. Assume polarity does not matter...?

Click to expand...

Stator wires should normally be WG and GY however, as stator output is AC it doesn't matter.



I'm not sure what's happening with that 3-way connector in your photo but it looks as if there's a brown/blue connected to a brown/green? Also, that apparently blue wire doesn't seem to belong there?

Thanks LAB -

The three way block connects to the neutral indicator switch by converting one leg of it to the red (ground) wire. The rest don't connect to anything. Came to me that way and all turn signal lights and the rest work properly (including the neutral light).

By examining the double ended two conductor female connector (not in the pic) it looks like it combined the two green/yellow striped wires coming from the harness while the single green/white must have connected to the other green/white going to the alternator.

There are no other wires in the area.

What's confusing is why the the color combinations on this bike do not match the wiring diagram in the technical manual.

Sound right?

ag12680 said:

What's confusing is why the color combinations on this bike do not match the wiring diagram in the technical manual.

Sound right?

Click to expand...

I'd say apart from the Mk3 console section the colour codes on the Mk3 diagram seem to match the harness wire colours reasonably well, so I can't explain why yours doesn't unless the harness has been modified or repaired as I wouldn't expect to see a brown/blue and a blue at that particular section of the harness?

L.A.B. said:

ag12680 said:

Wiring diagram says there should be green/white and green/ yellow coming from alternator

Click to expand...

Those wires should actually be white/green [WG] and green/yellow [GY] (green/white [GW] is the RH indicator/blinker circuit)

Click to expand...

They look like they actually are, and were just slightly wrongly described.

ag12680 said:

two green/yellow and one green/white coming from rectifier.

Click to expand...

One harness GY should go to the Edit: rectifier and then to the zener, the other GY goes to the assimilator, similarly, there should be two WG wires? One going to the rectifier and 2nd Zener, the other WG to the assimilator, therefore you appear to have a missing WG harness wire?.

Click to expand...

No missing W/G wire, just a "Series 1" Mk 3, which uses the earlier 3 wire assimilator (G/Y feed) , typically mounted to the top bolt of the air box, facing forward.

ag12680 said:

1. Have I damaged the alternator by running it shorted?

Click to expand...

Possibly not.

Click to expand...

It could be weakened, even an output test might not show that, but it is very fair to say possibly not.

ag12680 said:

2. Do the green/white and green/ yellow pair on one side?

Click to expand...

Normally, the stator WG would connect to the two harness WG wires, and the stator GY to the two harness GY wires.

Click to expand...

Not on a Series 1.

ag12680 said:

3. Assume polarity does not matter...?

Click to expand...

Stator wires should normally be WG and GY however, as stator output is AC it doesn't matter.

Click to expand...

Replacement stators commonly use only G/Y wire. Even a 3 phase may have 2 x G/Y with the 3rd being W/G.

I'm not sure what's happening with that 3-way connector in your photo but it looks as if there's a brown/blue connected to a brown/green? Also, that apparently blue wire doesn't seem to belong there?

Click to expand...

I think you will find that it is actually a Brown/GR (that you saw as Brown/Blue) wire, and that it is in a spare slot on the 5 way (the wire you thought it was connected to is one of the neutral sw wires, and is (or should be) connected to the RED wire). The Blue is also in a spare slot. As it is the earlier Series 1, the wiring harness had the "lights on" wires present (but not ever connected that I have seen).

NorComCycles said:

L.A.B. said:

I'm not sure what's happening with that 3-way connector in your photo but it looks as if there's a brown/blue connected to a brown/green? Also, that apparently blue wire doesn't seem to belong there?

Click to expand...

I think you will find that it is actually a Brown/GR (that you saw as Brown/Blue) wire, and that it is in a spare slot on the 5 way (the wire you thought it was connected to is one of the neutral sw wires, and is (or should be) connected to the RED wire).

Click to expand...

That central wire certainly looks brown/blue on my screen?



Agreed, the apparently brown/green neutral switch wire would normally connect to harness red.

That central wire certainly looks brown/blue on my screen?

Click to expand...

Upon making the pic larger, it looks more blue to me as well.
So to get it completely clear in my mind, I went to check the actual wiring. Hardly critical, as it is connected to nothing, but interesting, and might as well define it.

So, off to the workshop. I have 6 Mk 3 here currently (for various things) and the first one I looked at was by chance an early one with identical wiring, and the early assimilator.

With torch and magnifying glass to be sure, your eyes saw correctly, the wire is Brown/Blue, and it is connected to the capacitor, on the "non battery" pairing. The capacitor has double Brown/Blue connected either side of a double posted terminal, making it live all the time before the key. To disconnect the capacitor makes it dead, but also makes the ign switch dead as well, of course (though I think the other (later) type with a single (the deletion of this wire in question?, I have never bothered to look into it) and a double at the capacitor need not be connected for the bike to stay live).

I did not check the Blue wire, but assume it is headlight, so I still can only imagine it is about a "lights on" concept.

Sound right?

NorComCycles said:

With torch and magnifying glass to be sure, your eyes saw correctly, the wire is Brown/Blue, and it is connected to the capacitor, on the "non battery" pairing. The capacitor has double Brown/Blue connected either side of a double posted terminal, making it live all the time before the key. To disconnect the capacitor makes it dead, but also makes the ign switch dead as well, of course (though I think the other (later) type with a single (the deletion of this wire in question?, I have never bothered to look into it) and a double at the capacitor need not be connected for the bike to stay live).

Click to expand...

The (apparently) original later type harness fitted to my Mk3 has the ''2&1'' brown/blues [NU] at the 2MC.
Disconnecting either NU from the 2MC didn't isolate the ignition switch, however, the "new" harness I fitted last year has the ''2&2" NU' wires and does isolate the ignition switch if one NU is disconnected from the 2MC.

NorComCycles said:

I did not check the Blue wire, but assume it is headlight, so I still can only imagine it is about a "lights on" concept.

Sound right?

Click to expand...

I expect so, although there's no logical reason I can think of why the early Mk3 harness has an NU and a U wire at that location unless perhaps the original intention was to fit some kind of additional "lights on" relay for Canada as well as the standard silver can (3AW) assimilator? The only other logical explanation is the two wires are for the Interpol model?

L.A.B. said:

NorComCycles said:

With torch and magnifying glass to be sure, your eyes saw correctly, the wire is Brown/Blue, and it is connected to the capacitor, on the "non battery" pairing. The capacitor has double Brown/Blue connected either side of a double posted terminal, making it live all the time before the key. To disconnect the capacitor makes it dead, but also makes the ign switch dead as well, of course (though I think the other (later) type with a single (the deletion of this wire in question?, I have never bothered to look into it) and a double at the capacitor need not be connected for the bike to stay live).

Click to expand...

The (apparently) original later type harness fitted to my Mk3 has the ''2&1'' brown/blues [NU] at the 2MC.

Click to expand...

That is what I have always experienced.

L.A.B. said:

Disconnecting either NU from the 2MC didn't isolate the ignition switch

Click to expand...

Yes, removing the capacitor when an elec ign is fitted has no impact on the "2 and 1" type.

L.A.B. said:

however, the "new" harness I fitted last year has the ''2&2" NU' wires and does isolate the ignition switch if one NU is disconnected from the 2MC.

Click to expand...

The "Andover" replacement harness seems to have a mix of early and late, as demonstrated by the assimilator wires being the later 5 connection type (06.6393) but exiting the wiring loom from the 3 wire position (near the earth connection to the head steady) instead of lower near the battery.

L.A.B. said:

NorComCycles said:

I did not check the Blue wire, but assume it is headlight, so I still can only imagine it is about a "lights on" concept.

Sound right?

Click to expand...

I expect so, although there's no logical reason I can think of why the early Mk3 harness has an NU and a U wire at that location unless perhaps the original intention was to fit some kind of additional "lights on" relay for Canada as well as the standard silver can (3AW) assimilator? The only other logical explanation is the two wires are for the Interpol model?

Click to expand...

Whichever ( or whatever) the reason, I have never thought past the "must be some sort of lights on" as it really has no impact (to anything I do). I have noticed it, but never ever had to interact with it. In terms of this original post, knowing it is stock, and that there is nothing missing or wrong, is likely enough.

Although bikes do get changed around, and it can be difficult to tell, I doubt I have ever actually seen an Interpol (if I ever did, I did not know it).

NorComCycles said:

L.A.B. said:

however, the "new" harness I fitted last year has the ''2&2" NU' wires and does isolate the ignition switch if one NU is disconnected from the 2MC.

Click to expand...

The "Andover" replacement harness seems to have a mix of early and late, as demonstrated by the assimilator wires being the later 5 connection type (06.6393) but exiting the wiring loom from the 3 wire position (near the earth connection to the head steady) instead of lower near the battery.

Click to expand...

Yes, as was the new harness I bought (not from AN although it could be an AN harness) so the 06-6393 assimilator is now tucked away out of sight beneath the fuel tank which I really don't mind.

Epilogue:

Turns out that my alternator has two green/yellow wires instead of one green/yellow and one green/white per the wiring diagram in the factory tech manual.

I mistakenly put both of this into the double connector with two green/yellow wires coming from the harness and missed the one green/white coming from the harness.

Tested both zeners (good), put one green/yellow into the two green/yellow from the harness and the other green/yellow to the single green/white.

Bike now charges properly and FYI the shorting of the alternator for 20 miles of running did not cause a short or open coil.

Thanks all...

The ''Andover'' harness is actually a LAP part, AN do not make this harness.