Alternator wiring

Im trying to fit my old TD alternator to my disco 200tdi, the alternator physicly fits but there are some wiring issues.

The disco alternator has the main possitive and one wire for the warning light.

The TD engines alternator has three pins, and it wont work with the single wire on any of those three pins. I belive there are; ignision switch, warning light, and a constant possitive, but i dont know which is witch and if its worth re-re-wiring the eletrics or better to buy another disco alternator. Anyone know what the three pins are actually for?

Thanks, Richard.

from memory, it is 3am,,,, i will check and re post tho if im wrong.

heavy red 12+ to battery , thin black warning light, white senser pickup.

the alternator is grounded from the engine / earth strap.

there are faint markings on it..(the alternater)..

+ or batt this connects to the battery
T1 , warning light
T2 , not needed.

hope this helps

mick