2015 ram 1500 voltage regulator

[Honorarybacon]

I have a 2015 ram 1500 5.7 hemi the battery went dead out of no where one day changed the battery then had the alternator checked and was told the voltage regulator failed. Well I can’t find one on it and had an alternator guy tell me they aren’t in the alternator. So where is it located? Everything I have been seeing is telling me the PCM but not sure if that is accurate. Thanks in advance

 

[pacofortacos]

As far as I know the PCM controls the alternator. You could always wire in an external regulator if you wanted to.

 

[Honorarybacon]

Would it matter what type? I know nothing about cars and from looking there are many different looking ones

 

[pacofortacos]

I don't know off hand, but if you don't know anything about cars I am not sure if you want to do this as it isn't just a plug in type of thing.
You could always get a used PCM IF that is what has really failed, but you might want to do some testing first to confirm.

How did they test the alternator - on the vehicle or off of the vehicle?

 

[BossHogg]

I have a 2015 ram 1500 5.7 hemi the battery went dead out of no where one day changed the battery then had the alternator checked and was told the voltage regulator failed. Well I can’t find one on it and had an alternator guy tell me they aren’t in the alternator. So where is it located? Everything I have been seeing is telling me the PCM but not sure if that is accurate. Thanks in advance

Replacement regulators are about forty bucks and it is located on the positive battery terminal. Search the internet for "2015 Ram hemi voltage regulator".

 

[crazykid1994]

Replacement regulators are about forty bucks and it is located on the positive battery terminal. Search the internet for "2015 Ram hemi voltage regulator".

That is the battery sensor. Not the voltage regulator. That monitors battery health, output, and voltage. The pcm is what controls the alternator output.

 

[BossHogg]

That is the battery sensor. Not the voltage regulator. That monitors battery health, output, and voltage. The pcm is what controls the alternator output.

When I did a search for the voltage regulator, that is what popped up. In the past, the regulator was built into the alternator and was not a user-replaceable part or was attached to the alternator and was user replaceable. I always thought the device that is attached to the battery positive was the IBS.

So the question remains, is the regulator external to the alternator and if so, where is it? On both my trucks, it looks like the regulator is inside the alternator.

 

[crazykid1994]

When I did a search for the voltage regulator, that is what popped up. In the past, the regulator was built into the alternator and was not a user-replaceable part or was attached to the alternator and was user replaceable. I always thought the device that is attached to the battery positive was the IBS.

So the question remains, is the regulator external to the alternator and if so, where is it? On both my trucks, it looks like the regulator is inside the alternator.

It is internal to the alternator but still controlled by the computer. Quite a few vehicles have been that way. But the circuit fails in the pcm to tell the alternator to produce power or the alternator shorts out. Just replaced the alternator in my MILs 2010 Toyota Corolla. Has a 4 wire plug from the pcm and then the positive cable from the alternator. Internal regulator but externally controlled.
Yes, The device on the battery is an IBS that monitors voltage, amperage, and battery health to tell the pcm how to regulate the alternator for an “optimal battery health”

 

[Honorarybacon]

It is internal to the alternator but still controlled by the computer. Quite a few vehicles have been that way. But the circuit fails in the pcm to tell the alternator to produce power or the alternator shorts out. Just replaced the alternator in my MILs 2010 Toyota Corolla. Has a 4 wire plug from the pcm and then the positive cable from the alternator. Internal regulator but externally controlled.
Yes, The device on the battery is an IBS that monitors voltage, amperage, and battery health to tell the pcm how to regulate the alternator for an “optimal battery health”

My alternator doesn’t have the regulator in it.

 

[crash68]

My alternator doesn’t have the regulator in it.

@crazykid1994 post you quoted explains the Ram charging system (how the ECM controls the alternator charging voltage). Your charging problem is either the alternator or the IBS

 

[BossHogg]

My alternator doesn’t have the regulator in it.

Since an alternator does not produce 12 volt DC power, there has to be a voltage regulator and it has to be someplace. The folks that told you your voltage regulator is bad, how did they determine that? I find that questionable. If they are able to measure the alternator's output before and after the regulator, the only way to determine if the issue is the regulator, then they can tell you where the regulator is located.

 

[crazykid1994]

My alternator doesn’t have the regulator in it.

It’s probably non serviceable. Just like the one on my MILs Toyota. It’s fully internal. A Toyota alternator was 448$. Ended up buying a refurbished unit for 230$. Is there a plug attached to the alternator other than the positive lead? If so that’s the regulator.

 

[pacofortacos]

I don't know of many if any mopars that used an internal voltage regulator.
The regulator has been/is internal to the PCM or external regulator.
What you are thinking of internally are the diodes that convert the signal to DC.

From what I can see on pictures, since I didn't go out an look, is it is still a 2 wire plus positive cable system. The 2 wires control the field which is how the voltage is controlled.
The old old systems used a 1 wire plus positive cable system. It had the one field wire internally grounded.

The alternator will not put out any amps/volts if the field isn't energized - and this is done via the pcm voltage regulator.

Unless they have changed over the past years ( I don't wrench professionally any longer) this is how mopar has done it for decades.

 

[pacofortacos]

Since an alternator does not produce 12 volt DC power, there has to be a voltage regulator and it has to be someplace. The folks that told you your voltage regulator is bad, how did they determine that? I find that questionable. If they are able to measure the alternator's output before and after the regulator, the only way to determine if the issue is the regulator, then they can tell you where the regulator is located.

The voltage is rectified via diodes internally in the alternator.
Using a scope, you can see if a diode/s are failing and going bad - we used to use a big Sun scope system for ignition and charging problems back in the day.

 

[RamDiver]

I have a 2015 ram 1500 5.7 hemi the battery went dead out of no where one day changed the battery then had the alternator checked and was told the voltage regulator failed. Well I can’t find one on it and had an alternator guy tell me they aren’t in the alternator. So where is it located? Everything I have been seeing is telling me the PCM but not sure if that is accurate. Thanks in advance

Check this post from @yoda to see if it provides more clarity. It has a summary of the Ram charging system.

Voltage regulator in PCM fried??

Hello everyone... After spending all day researching 4th gen ram charging systems I have a problem to share. Yesterday, I finished rebuilding (cam, lifters, etc) my 2015 ram 1500 and everything was charging correctly upon completion. However, two nuts on my rocker arm assembly were making a...

www.ramforum.com

 

[Nicholas Cove]

I have a 2015 ram 1500 5.7 hemi the battery went dead out of no where one day changed the battery then had the alternator checked and was told the voltage regulator failed. Well I can’t find one on it and had an alternator guy tell me they aren’t in the alternator. So where is it located? Everything I have been seeing is telling me the PCM but not sure if that is accurate. Thanks in advance

Voltage regulation is directly controlled by the pcm on these trucks.

 

[RamDiver]

I copied & pasted the details below from yoda's post referenced above. This also identifies that the pcm controls regulation of the alternator voltage.

08 - Electrical / 8F - Engine Systems / Charging / Operation
OPERATION

1 - PCM

2 - PDC

3 - Battery

4 - Generator

5 - Feed Back Circuit B+

6 - Control Circuit

The charging system is turned on and off with the Powertrain Control Module (PCM) and ignition switch with engine running. The field circuit will not be energized until engine is running and ignition switch on. This voltage is connected through the PCM and supplied to one of the generator field terminals (Gen. Source B+) at the back of the generator. The generator is internally grounded. The generator regulates the field using pin-1 of the field connector (high side driver).

The generator is driven by the engine through a serpentine belt and pulley, or a decoupler pulley arrangement.

The PCM receives a voltage input from the generator (5) and also a battery voltage input from the Power Distribution Center (PDC), it then compares the voltages to the desired voltage programed in the Electronic Voltage Regulator (EVR) software, and, if there is a difference it sends a signal to the generator EVR circuit to increase or decrease output. It uses a Pulse Width Modulation (PWM) to send signals to the generator circuitry to control the amount of output from the generator. The amount of DC current produced by the generator is controlled by the EVR circuitry contained within the PCM (1).

All vehicles are equipped with On-Board Diagnostics (OBD). All OBD-sensed systems, including EVR 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.

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 lamp is located on the instrument panel.

Voltage is monitored at the B+ terminal stud to insure it is connected. If the B+ cable is loose, the PCM will shut down generator field. Because of this new feature, pin-2 of the field connector is internally connected to the B+ terminal.

 

[Marshall]

The voltage is rectified via diodes internally in the alternator.
Using a scope, you can see if a diode/s are failing and going bad - we used to use a big Sun scope system for ignition and charging problems back in the day.

You can also do a quick check on diodes with a muli meter, as well see what the voltage reads on the battery when the truck is running , should be about 14.4 volts or somewhere close.
While I have worked on many older ones, I have not on these new trucks, they always worked.
If you are not up on electrical on these things, don't start ******** with the PCM
Back in the stone age , you just shorted the small wire out and that gave you full charge off the generator or alternator, but if left on, would fry the battery, or kill it the relay was simple, so easy fix. a wack with a wrench worked , or just clean the points.
Now ,I am lost. First I would look in the fuse box for a relay.

OK as my usual, I post with out reading everything, sounds like no point in looking for a relay in fuse box, that would be too easy.

 

[Philip Gao]

My car has the regulator problem is the voltage is too high, I have a simple tool found this problem, it is about $10 like following image

When my drive the car, the meter show a 15-16V high voltage, some warning comes, I really want to replace this part, I found it built inside the alternator, finally I change a new alternator, the problem is gone, you can use a voltage meter to test the charging voltage when the engineer running, the correct reading is about 14V

 

[Marshall]

I was looking at a auto repair site , rainman maybe
He had a high output voltage
So he installed a new alt. And fixed the problem