c5500 charging problem

[towjoe]

just curious if anyone on here would happen to know where I could find the charging system wiring diagram for a 2005 chevy 5500? I have one that will not charge right, replaced both alternators, cleaned all the terminals I could find, tested all 3 batterys and still only runs 12 volts while running. any ideas or help would be greatly appreciated

 

[bucket]

I think they are controlled by a BCM or something. The company I work for now has 3 4500's and 2 6500's and none of them charge on startup. They only charge after running for a minute or two. There must be a module or timer of some kind that turns on the alternator.

We also have a c7500 but it doesn't seem to have the delayed alternator thing going on.