Question about 1990 Plymouth Voyager
It is the ECM (Engine Control Module) you are looking to find. It is located between the battery and the firewall it mounts on.
This is what houses the regulator and it needs to be replaced as a unit.
You can find it online for about $200+ core.
Posted on Nov 15, 2009
Hope this is helpful, Ian
DESCRIPTION - CHARGING SYSTEM
The charging system consists of:
† Decoupler Pulley (If equipped)
† Electronic Voltage Regulator (EVR) circuitry
within the Powertrain Control Module (PCM)
† Ignition switch (refer to the Ignition System section
† Battery (refer to the Battery section for information)
† Battery temperature sensor
† Voltmeter (refer to the Instrument Cluster section
† Wiring harness and connections (refer to the
Wiring section for information)
† Accessory drive belt (refer to the Cooling section
for more information)
OPERATION - CHARGING SYSTEM
The charging system is turned on and off with the
ignition switch. The system is on when the engine is
running and the ASD relay is energized. When the
ASD relay is on, voltage is supplied to the ASD relay
sense circuit at the PCM. This voltage is connected
through the PCM and supplied to one of the generator
field terminals (Gen. Source +) at the back of the
The generator is driven by the engine through a
serpentine belt and pulley or decoupler pulley
The amount of DC current produced by the generator
is controlled by the EVR (field control) circuitry
contained within the PCM. This circuitry is connected
in series with the second rotor field terminal
A battery temperature sensor is used to sense battery
temperature. This temperature data, along with
data from monitored line voltage, is used by the PCM
to vary the battery charging rate. This is done by
cycling the ground path to control the strength of the
rotor magnetic field. The PCM then compensates and
regulates generator current output accordingly to
maintain system voltage at the targeted system voltage
based on battery temperature.
All vehicles are equipped with On-Board Diagnostics
(OBD). All OBD-sensed systems, including EVR
(field control) circuitry, are monitored by the PCM.
Each monitored circuit is assigned a Diagnostic Trouble
Code (DTC). The PCM will store a DTC in electronic
memory for certain failures it detects. Refer to
On-Board Diagnostics in the Electronic Control Modules(
Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULE - DESCRIPTION) section for more DTC
The Check Gauges Lamp (if equipped) monitors:
charging system voltage, engine coolant temperature
and engine oil pressure. If an extreme condition
is indicated, the lamp will be illuminated. This is
done as reminder to check the three gauges. The signal
to activate the lamp is sent via the PCI bus circuits.
The lamp is located on the instrument panel.
Refer to the Instrument Cluster section for additional
The Electronic Voltage Regulator (EVR) is not a
separate component. It is actually a voltage regulating
circuit located within the Powertrain Control
Module (PCM). The EVR is not serviced separately. If
replacement is necessary, the PCM must be replaced.
The amount of DC current produced by the generator
is controlled by EVR circuitry contained within
the PCM. This circuitry is connected in series with
the generators second rotor field terminal and its
Voltage is regulated by cycling the ground path to
control the strength of the rotor magnetic field. The
EVR circuitry monitors system line voltage (B+) and
battery temperature or inlet air temperature sensor
(refer to Battery Temperature Sensor or Inlet Air
Temperature Sensor for more information). It then
determines a target charging voltage. If sensed battery
voltage is 325 mv or lower than the target voltage,
the PCM grounds the field winding until sensed
battery volage is 325 mv above target voltage. A circuit
in the PCM cycles the ground side of the generator
field up to 250 times per second (250Hz), but
has the capability to ground the field control wire
100% of the time (full field) to achieve the target
voltage. If the charging rate cannot be monitored
(limp-in), a duty cycle of 25% is used by the PCM in
order to have some generator output. Also refer to
Charging System Operation for additional information.
The electronic voltage regulator is not a serviced
separately. If replacement is necessary, the PCM
must be replaced.
Posted on Jul 30, 2009
a 6ya Mechanic can help you resolve that issue over the phone in a minute or two.
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click here to Talk to a Mechanic (only for users in the US for now) and get all the help you need.
Posted on Jan 02, 2017
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