Alternator wiring How cam I determine if I need an alternator or just a voltage regulator?

In a voltage regulator plug, the wires may not necessarily carry the same voltage. The voltage regulator is a component in a vehicle's electrical system that controls and regulates the voltage produced by the alternator, ensuring a consistent voltage output to the battery and other electrical components.
In the plug of a voltage regulator, there are typically multiple wires, each serving different purposes and carrying different voltages. For instance:
1. **Voltage Input and Output Wires:** These wires might differ in voltage. The input wire connects to the alternator or battery, carrying the higher voltage that needs regulation. The output wire, connected to the electrical system, carries the regulated voltage for the vehicle's operation.
2. **Ground Wire:** This wire is crucial for completing the circuit and ensuring proper functioning of the voltage regulator. It does not typically carry a voltage; instead, it serves as the return path for the electrical current.
3. **Sensing Wire:** In some regulators, there might be a sensing wire that monitors the system voltage. This wire doesn't usually carry a high voltage but rather acts as a feedback mechanism for the regulator to adjust its output.
It's important to identify and understand the wiring configuration of the voltage regulator plug, as incorrect connections or wiring can lead to electrical issues or even damage to the vehicle's electrical system. Referencing the vehicle's service manual or wiring diagrams specific to the make and model can provide accurate information about the voltage levels and the purpose of each wire in the voltage regulator plug.

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The capacity of the alternator ( 35 amp or 100amp ) will make little difference to charging a battery. It has to do with the voltage regulator which may be internal in the alternator or external on the engine bay. The other fault that will not allow a battery to charge is the rectifier as if a diode has burnt out then the voltage that is being regulated is ac and it will not work anyway. The capacity of the alternator is determined by the total current draw when everything is switched on and should be around 10 amps more than what is required. IT not then the battery will slowly drain down because the alternator is not capable of running every thing and charge the battery as well. I suggest that an accredited auto electrician be engaged to sort this problem out

there are three wires at the regulator two from the alternator and one that goes to the battery see if there is voltage at the two from the alternator if so the regulator is bad

Hello, again, again Bridget. First I sent you explanation of the ignition system and I gave you my best guess---ignition module on your 1994 Plymouth with V6 3.4 L engine.

As far as voltage regulation goes there isn't any external devise to do this. This voltage voltage regulation take place inside the alternator after the three phase AC voltage is turn into none regulated DC voltage. Now this DC voltage goes thru a voltage regulator that built into the alternator where the output DC voltage is 13.8 to 14.1 DC Volts. Now, the alternator is regulated for current by the it wire windings in the alternator. Larger the copper wire the more current the alternator will produce. GB.....stewbison

you should have 12.5 volts with engine off at battery and 14.4v with engine running and charging system working. Is alternator light on? please rate, thx.

There are different versions and 1989 is too old to get on line. here is 1993, so take with caution. Also check the fusible link.

Battery Positive Voltage (B+) Output
The generator (alternator) output is supplied through the Battery Positive Voltage (B+) output connection to the battery and electrical system. I Circuit
The I circuit, or ignition circuit is used to turn on the voltage regulator. This circuit is powered up with the ignition key in the RUN position. This circuit is also used to turn the indicator on if there is a fault in the charging system operation or associated wiring circuits A Circuit
The A circuit, or battery sense circuit, is used to sense the battery voltage. This voltage is used by the regulator to determine the output. This circuit is also used to supply power to the generator (alternator) field coil. This circuit is connected back to the load distribution point and is a protected circuit. S Circuit
The S circuit, or stator circuit, is used to feedback a voltage signal from the generator (alternator) to the regulator. This voltage, typically 1/2 battery voltage, is used by the regulator to turn off the indicator.

VOLTAGE REGULATOR IS LOCATED BEHIND BATTERY.YOU PROBABLY MIGHT HAVE TO REMOVE BATTERY TO REMOVE THE VOLTAGE REGULATOR.

You need to connect a meter across the battery terminals to determine whether the battery is being charged by the alternator. Compare the voltage at rest to that obtained when the engine is running. It should be about 12 volts at rest and then rise to approximately 14 volts. The voltage regulator (which controls how much voltage is being produced by the alternator and operates the charge lamp on the dashboard) on some vehicles is separate to the alternator. If the voltage is rising to within specifications as previously mentioned, the wiring to the lamp may be being earthed somewhere along it`s run to the alternator/regulator. Ian

Here is what you need.



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if you can carefully put a metal wrench on the rotating pulley of the alternator and felt a magnetism attracting the metal wrench, then your alternator is charging. if there is no magnetism, then the alternator is not charging...

another test is to measure the voltage on the small wires that went in to the alternator that says "F" for field, it should measure battery voltage...that is the voltage from the regulator..that means your regulator is working...but the altrntor is not..

without that battery voltage, then the regulator is he culprit...



pls be carefull...

hope i was able to solve ur problem..

pls rate me.. tnx, drcool..