2005 Nissan Altima charging problem

I just bought a 2005 Nissan Altima SL with a 3.5 liter engine. It will charge at idle but not going down the road. Belt tension is ok. How does the charging system in this vehicle work and dies anyone have a colored schematic so I can diagnosis the charging system.

CHARGING SYSTEM

System Description
The generator provides DC voltage to operate the vehicle's electrical system and to keep the battery charged.

The voltage output is controlled by the IC regulator.

Power is supplied at all times to generator terminal B through:
- 120 A fusible link (letter a , located in the fusible link box).

Power is supplied at all times to generator terminal S through:
- 10 A fuse (No. 26, located in the fuse and fusible link box).

Terminal B supplies power to charge the battery and operate the vehicle's electrical system. Output voltage is controlled by the IC regulator at terminal S detecting the input voltage. The charging circuit is protected by the 120 A fusible link.

The generator is grounded to the engine block.

With the ignition switch in the ON or START position, power is supplied:
- through 10 A fuse [No. 14, located in the fuse block (J/]
- to combination meter terminal 22 for the charge warning lamp.

Ground is supplied to terminal 14 of the combination meter through terminal L of the generator. With power and ground supplied, the charge warning lamp will illuminate. When the generator is providing sufficient voltage with the engine running, the ground is opened and the charge warning lamp will go off.

If the charge warning lamp illuminates with the engine running, a fault is indicated.

On this Nissan I'm working on can you tell me how the bulb circuit works. I ask the son of the alternator light comes on engine off when he turns key to on. He said it doesn't and if that's the case I'm assuming that a burnt out light is causing his no charge condition

I’ve seen this a few times years ago the bulb was the problem

On nissans roughly the same year