105HZJ Alternator not charging.

[Blue Hippo]

I hope I am doing this right
I have a 105 HZJ LC. Dubbed the Blue Hippo. We tour Southern Africa in her and use her from time to time for Conservation Projects. She has been experiencing an intermittent electrical fault recently.
The T-belt; Drain water lamp; air filter lamp and battery lamp all flashed on and off intermittently. Reasearch indicated that it could be a faulty earth/ground. So we checked all grounds and found nothing. I then stripped the dash and chased wires, cutting out obsolete phone systems etc. The problem did not go away until I checked the plug at the back of the alternator. The alternator plug was in pieces with connections making contact intermittently. So I pulled the alternator which was working fine. Bought a new 3 pin plug and replaced the plug and alternator. Problem solved no flashing lights.
But I soon detected that the alternator is now not charging. I have checked continuity in the circuits and we have continuity. I have a spare Alternator that I take along for long trips into the bush, which I wired in and again there is no charge. I have added an extra ground and removed it to see if that helps but we still have no charge. I am currently checking fuses but the fuses all seem to be in order. I am at my wits end. I do not know what to do. Any help would be greatly appreciated.

 

[badlander]

I would suspect that the brushes are at their limit of wear. The wire only lets them move so far then they will start to burn up from arcing and as this worsens you will most likely see a drop in output voltage, especially at idle. This also causes the plug to get very hot as well which may be what caused yours to get brittle. I actually had an alternator fire caused by this in my old van. Worn or sticking brushes could also cause the intermittent charging you are experiencing.

 

[Blue Hippo]

Thanks Badlander, I swapped in the spare alternator that I have and it is doing the same thing. That alternator is brand new out the box and I had it bench tested when I bought it.
I did some more testing and found that I have no circuit on the middle pin in the plug. Which if I understand the workshop manual correctly is the ignition wire. I have wired in a bypass to test my theory that this wire might be the fault but there is no change. I have however found multiple splices into the wiring harness into obsolete alarm systems etc. which I have cut out and cleaned up. Hopefully we will get to the bottom of this issue.

 

[badlander]

O.K., I missed the part of swapping in the spare alternator. Looks like you do have some harness issues.
Good luck. Sounds like you are on the right track.