925 starter/ charging issues

[twrecks]

Hey everyone, I have a 925 series truck I am having a time with. I replaced the "brain Box" a while back, and have since replaced the alternator and recently the starter. I was trying to reinstall the starter outside in the sark and got one of the wires crossed and fried it before I could get it unhooked. I got everything back in where I think is the right place. I has been starting fine until recently. My batteries are reading fine, I unhooked and charged all, it will start if I put jumper boxes on it but not on it's own and my volt meter is in the yellow to red. It seems almost as if the alternator is not charging. I have looked all over trying to find a printable wiring diagram so I can take it out to the truck and check it all out. Could I have missed a wire that is supposed to be charging back, did I fry the brain box?? pulling my **** hair out!!! any help appreciated

 

[74M35A2]

Sounds like your alternator is out to lunch. Best first and simple check is to leave it all together, start the engine (jump it or whatever), and put a digital volt gauge at the slave port. Inside is +, outside is -. You should have greater than 25.6V with the truck running. Closer to 28v or so is optimal. If not, then the alternator is not working and you can try to figure out why by seeing if it is getting the excitation signal it requires through one of the small wires connected to it (sorry, I don't know which one without seeing a schematic). Also check the alternator belt, pulley, and belt tension. People here have had issues with all 3 of those in separately and in addition to electrical issues.