Battery Charging System - 2001 Chevy Venture

There was a post in the automotive forums recently asking about the battery charging system operation. 
Here is some information I gathered from a couple of repair manuals that might help in troubleshooting and repairing
any problems that you might have in this area.

Battery Charging System - Description & Operation

The charging system includes the following major components:

  • The Battery
  • The Generator (some call it an alternator)
  • Two (2) fuses Under-hood fuse #30 (10 Amp) [ALT SENSE/Generator] &
    Fuse panel (inside passenger compartment) fuse #36 (10 Amp) [Instrument Panel, BCM, etc.])
  • Power train Control Module (PCM)
  • All associated wiring & connectors, including 2 "Fusible links" A & Z (see schematic below)

Basic Operation: 

  • The generator supplies voltage to operate the electrical system and charge the battery.
  • The PCM sends a "turn-on" signal to the generator when the engine is running (turns on the internal regulator).
  • Terminal F is connected to the voltage regulator internally and externally to the PCM (I don't see it on the schematic). When the regulator detects problems in the charging system, it grounds this signal to "tell" the PCM.
  • When a problem is detected, the PCM sends a (serial) message to the instrument panel (turns on "charge light").
  • The "Sense" circuit receives system voltage (terminal D in schematic) at all times (through a fuse).  This is a "reference" voltage for the charging system.

Other information:

  • The "Charge Indicator" is displayed when; a) the PCM detects less than 11 volts or more than 16 volts from the generator, b) a test is performed at ignition, and c) ignition is on but the engine is off.
  • Fusible links (A & Z) protect the generator & battery.

Here is the schematic for the battery charging system.  Click on it for a larger view.
Battery Charging System Schematic

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