Yes 2002 F250. The alternator I am installing looks identical to the one I removed. I found picture that showed the difference in the 3g and 6g, I have/had a 6g alt.

 

Ok, I am looking at a 2002 diagram, and it shows the same lightgreen/red which triggers the alt to go online.

It shows a yellow/white as the output wire to the battery, and also shows a orange/lightblue which seems to be the feedback wire, which also goes to the battery.

With the truck off, you should have 12 volts on the yellow/white and the orange/lightblue. Make sure you put the negative meter lead on the alternator case when you are measuring voltages to make sure the alt has a good ground.

With the key off you should have zero volts on the lightgreen/red, and with the key on you should have some sort of voltage on the wire which triggers the alt to charge.

 

The new alt take a little time to dissapate the field lead on the grn/red, but it does go to near 0. The others do have a good connection to the battery. Key on, the grn/red wire has battery voltage. The wiring seems to be correct. In all of the diagrams I have seen, the grn/red wire needs resistance/load. This makes me think that the cluster is not turning the alt on.

 

Ok, the dealership programmed my cluster to my VSM to my truck. Now I have an ABS light and still not charging. The mechanic said it was not communicating with the ABS module, and was dumb founded when after he finished, I showed him my door ajar light that only goes out with both front doors open. Cluster and VSM are new and both working, fuses are good. Does the alt connect to any other modules?

 

The light turned off on my way home from work. Alt is still not charging, and I have an RGA for. I am almost to the point of dropping it off at a dealership and telling them to call me when it's right.