T880 charging issues

Truck has an x15 and is still under warranty but the dealer is closed and was hoping i might be able to diagnose it myself.

The alternator is not charging at all. The battery connections are fine and not corroded, i didnt put a multimeter on it yet, is there a fuse for the charging system? The batteries are all in good shape, i tested them all.

 

If the truck wasnt under warranty i would have a spare, and wouldnt be waiting on the dealer. It only has 77,000 miles on it unfortunately but i do have 5 year 500,000 on the truck. One other time when i had to jump it off when it sat for two weeks the alternator wasnt charging but a power cycle fixed the issue and it never came back again.