Charging System - Generators & Regulators: Operation

Amperage produced by generator is controlled by Electronic Voltage Regulator (EVR) circuitry within Powertrain Control Module (PCM). EVR circuity is connected in series with generator field driver terminal and ground. A Battery Temperature Sensor (BTS), located on PCM printed circuit board, is used to sense battery temperature. BTS cannot be serviced separately. If BTS is found faulty, PCM must be replaced. Sensed battery temperature and data from monitored line voltage is used by PCM to adjust battery charging rate. This is accomplished by cycling ground path to control strength of generator rotor magnetic field. PCM compensates and regulates generator amperage output accordingly. PCM monitors critical input to control fuel injection, ignition, emission and other engine management functions. PCM is also programmed to monitor the following charging system-related circuits.

Battery feed to PCM.
Generator field control.
Battery charging voltage (high and low).

NOTE: DTC is erased from memory if failure does not reoccur after 50 engine starts.

If a problem is sensed in a monitored circuit, a Diagnostic Trouble Code (DTC) will be stored in PCM memory. Voltage indicator light and Malfunction Indicator Light (MIL) will illuminate, provided specific criteria have been met. DTCs can be retrieved by using odometer or Chrysler's Diagnostic Readout Box (DRB-III).