Pontiac Repair: 2000 Pontiac Montana Charging system, pontiac montana, lamp control

Question
Recently I purchased a 2000 Pontiac Montana and I found there is some sort of charging problem. So far I have tested the alternator it was good. Tested the starter and starter cylonoid...was bad and replaced. Tested battery it was bad
so i put a new one in. I'm stuck with the battery light coming on when i start it and its still not charging it sounds like the alternator is not engaging but it tested good when i took it to autozone they tested it twice. I've checked all my fuses on the relay block and the dash fuses on passenger side. Was told it
might be something to do with the brown wire that runs to my gage cluster from the single plug on the side of the alternator but I do not want to go replacing wires without getting a second opinion.

Answer
Hi Darryl:

the extra wire you are speaking of is the field control wire and it goes to the engine control module (computer) the engine control module controls the voltage regulator in the alternator. there could be an issue with that wire between the alternator and the computer. The computer could be bad or have a bad ground connection going to it not allowing it to control the alt. are you sure it's not charging or is just the light on? With the Van running you should have over 14 volts ate the battery If you do then there could just be an issue with the lamp control to the cluster. if it's not it indeed is not charging. Good luck :)