TR6 TR6 alternator wiring?

[Airfix]

My 1976 TR6 alternator has 3 connections, 2 large spades and and 1 small.
The ignition light wire connects to the small spade, a thick brown wire from the battery cable multi connector to the middle large spade. The lower large spade is unconnected.
I am confused, all of my wiring diagrams show all 3 connections being used.
I am currently having trouble with no charge and the ignition light staying on, just had the alternator rebuilt reistalled it and the problem remains the same.
Appreciate if somebody could have a look at their '76 and count the wires going into the alternator plug.
Thanks.

 

[DNK]

I am not familiar with the later 6's,but according to Dan's Skimatic, there should be 2 large N wires,and 1 NY to the light.

 

[Aldwyn]

Here is the alt in my '76...

Looks like one large connection, and one small!

 

[MadMarx]

I could imagine that one of the diodes are burned through.
These Lucas alternators are very known to burned through diodes.

Cheers
Chris

 

[dklawson]

From Dan Master's corporate site:
https://www.advanceautowire.com/tr2506.pdf
See page 8 for the '76 TR6

It shows the two heavy gauge browns should join together after leaving the alternator. Some alternators require both a sense ( S ) wire and battery ( B ) connection. It could be that without the second brown wire being connected you aren't allowing the regulator circuit to get the feedback it needs to know to turn on and charge the battery.

Your first post implies you have several wiring diagrams to reference. Compare them to the PDF above. All the 1973 and later TR6 diagrams in the PDF show the two heavy wires connected. I'd install a heavy gauge wire in the open spot on the plug and connect it at some safe location to the heavy gauge brown wire that's already there. The diagrams indicate that this won't create a problem... and it may solve your problem. However, the questions are... how long has your car been failing to charge, and why did it work before without the additional wire... while now it doesn't?

 

[Airfix]

Thanks for all the replies, my is the same as Aldwyn's photo above, I have a large colour print out of the DM diagrams and that is what got me wondering.
It worked for years until a couple of days ago, had it rebuilt and the problem persisted
I took the newly rebuilt alternator back to the shop and they found a loose wire inside although they claim it was working when then tested it the day before. Reinstalled it a second time and it's all good now and charges nicely with the 1 large brown wire which connects the baterry multi connector and the small brown/yellow wire running from the "ign" light in the dash.
I do have a small brown wire below the alternator which also comes from the battery multi connector but it's too small to connect to my 3rd alternator spade connector, maybe this was the "extra" wire shown on DM's diagrams and used for a different model alternator at production.
Cheers.