I've had hell of a job trying to figure the wiring out on this alternator
if you look at the label on the alternator and wire it up to match the label it wont work
I've spent two weeks taking the thing to bits and rewiring it up
pic here shows the label on the alternator

i need some clever people help :) alternator wiring
so working from the diagram i put the light feed (L) to the left pin the one nearest the alternator body hope your with me so far

i need some clever people help :) alternator wiring
after trying that for god knows how many time i messaged Tb one and asked him if he knew what the light feed would be negative or positive
he confirmed it was a earth (-) which is how i had been wiring it up
so back to google and research a bit more i come up with several pics of the plug on the alternator and wiring diagrams.
They were showing a different way of wiring up than the diagram on the alternator was showing here's a example

i need some clever people help :) alternator wiring
as you can see from the lugs on the plug its wired up the opposite way round that the diagram on the alternator body
Ive now wired it up as the diagram and it works
i hope this helps others if ever they come across a similar problem wiring up a alternator