Please help !!! alternator not charging

[buckwheat1]

I can not get the forum search to work so I am going to ask.

I am working on a 69 p-10 with 3 wire internally regulated alternator and can not figure out why the alternator is not charging.

Here is what I have done if someone could please tell me what I am doing wrong.

Original wiring was cut and spliced so many time I decided to run a new wire to the field terminal on the alternator because I was not getting any voltage to the original wire. I do not think the alternator has ever worked since I have owned the truck. We always kept it on a trickle charger but have been stranded a few times.

Ran a new wire from the ignition switch run position to a LED on the dash then then from other side of LED down to the alternator terminal. As far as I understand the led should light when the ignition is on but the truck is not running then go off when the alternator is charging. Or the terminal on alternator should be ground until the alternator is excited the should go to positive? Is this true? I am not getting ground continuity to ether of the terminals on the alternator?