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DIY/ External voltage regulator conversion

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Old Nov 30, 2019 | 03:32 PM
  #71  
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Originally Posted by psycobilly64
Ok, this is a write up on how to do an external voltage regulator conversion on any and all Chryslers with the reg in the ECM and an unregulated alternator. Till now, if you have charging issues with these trucks you had to replace a $3-500 computer. I did this conversion for $43.28 after sales tax. This can also apply to other trucks if you'd like add a second alt, or the wiring is fried.

Here is a list of parts that will be needed with prices as of 8/3/2011.
Regulator part #
MPI 2VR1 price $13.99
Regulator plug/pigtail part #
BWD PT173 price $8.49
1 coil of 14ga wire $5.99
1 pack of butt connectors $5.99
1 pack of ring terminals $5.99

Attachment 62720

These are the prices and part #s at my local O'Reilly.
Also a couple of self tapping screws.


The first thing you need to do is remove the little plastic box on the back of the alt.
Attachment 62721
Attachment 62722

Tape it up so it won't short out and tuck it out of the way (you will not be using it).
Attachment 62723

Find a good solid place on the firewall or inner fender to mount the regulator. If you don't have a place with a good ground, you can run a ground wire off one of the mounting screws. I mounted mine behind the battery on the metal fenderwell so no need for a ground wire on mine.
Mount the reg using the self tapping screws making sure you have enough room for the plug to stick out from it.

Attachment 62724

Cut two lengths of wire long enough to reach from the alt to the regulator. Crimp a ring connector large enough to fit the bolts the plastic block (removed in step 1) was attached to on to each one. Put them on and tighten the nuts down.
Attachment 62725

Once the wires are connected to the alt, cut a wire long enough to reach from the reg to an ignition pos of your choice. Take one of the wires from the alt (doesn't matter which) and the wire from the ignition pos and crimp them into one end of a butt connector.
Attachment 62726

Take the doubled wire (batt and alt) with the butt conn already attached and connect it to the TOP terminal on the pigtail. Take the other wire from the alt and attach it to the other terminal of the pigtail using a butt connector. Plug the pigtail into the reg, route the wires out of the way and reinstall the battery.
Attachment 62727
Attachment 62728

Start your truck and make sure it's charging properly. If so then you're done!

Take the money you saved from not buying a new comp, buy a six-pack and another upgrade for your truck!!
Attachment 62729

DOWNSIDE TO THIS MOD__ The only downside is that after doing this, your check engine light will stay on since it has no signal from the alt. There is no way I know of to prevent this, but someone here might have an idea. If that is an issue to you, then this conversion may not be for you!
The best write up I've seeing ever!! Thank you...I thought I was having the high voltage but when I measure the voltage at the battery it is showing 14.8 or so..it has been creeking up a bit and the gauge inside stays at 8-10 for a few seconds then bumps up to the 14 range..WHAT is the correct voltage the alternator should be putting to the battery?
I've been told the slow is due to the regulator GOING OUT...is that the case in your opinion?

Ive got ll the wires made per your excellent pics and ready to go BUT if it is ok charging at 14.84 then will wait to see

Thanks again for the writeup and looking forward to the answer
 
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Old Dec 4, 2019 | 02:36 PM
  #72  
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Originally Posted by psycobilly64
Ok, this is a write up on how to do an external voltage regulator conversion on any and all Chryslers with the reg in the ECM and an unregulated alternator. Till now, if you have charging issues with these trucks you had to replace a $3-500 computer. I did this conversion for $43.28 after sales tax. This can also apply to other trucks if you'd like add a second alt, or the wiring is fried.

Here is a list of parts that will be needed with prices as of 8/3/2011.
Regulator part #
MPI 2VR1 price $13.99
Regulator plug/pigtail part #
BWD PT173 price $8.49
1 coil of 14ga wire $5.99
1 pack of butt connectors $5.99
1 pack of ring terminals $5.99

Attachment 62720

These are the prices and part #s at my local O'Reilly.
Also a couple of self tapping screws.


The first thing you need to do is remove the little plastic box on the back of the alt.
Attachment 62721
Attachment 62722
MY QUESTION IS REGARDING THIS PIC WITH THE 4 EYELETS THE 2 IN THE SQUARE ONES ARE TAPED AND NOT USED...DO I NEED TO GET RID OF THE OTHER 2 WIRES ON THE END OR DO I RECONNECT THEM TO THE ALTERNATOR...

I did the repair but did not connect the 2 large wires and it started smoking and I changed them back to the regular black box and it is still smoking... I may be needing a new alternator now either way BUT want to make sure if they still attach or NOT and what to do with them..you have the 2 middle wires with the square tabs taped but not the other 2 with the big wires
Tape it up so it won't short out and tuck it out of the way (you will not be using it).
Attachment 62723

Find a good solid place on the firewall or inner fender to mount the regulator. If you don't have a place with a good ground, you can run a ground wire off one of the mounting screws. I mounted mine behind the battery on the metal fenderwell so no need for a ground wire on mine.
Mount the reg using the self tapping screws making sure you have enough room for the plug to stick out from it.

Attachment 62724

Cut two lengths of wire long enough to reach from the alt to the regulator. Crimp a ring connector large enough to fit the bolts the plastic block (removed in step 1) was attached to on to each one. Put them on and tighten the nuts down.
Attachment 62725

Once the wires are connected to the alt, cut a wire long enough to reach from the reg to an ignition pos of your choice. Take one of the wires from the alt (doesn't matter which) and the wire from the ignition pos and crimp them into one end of a butt connector.
Attachment 62726

Take the doubled wire (batt and alt) with the butt conn already attached and connect it to the TOP terminal on the pigtail. Take the other wire from the alt and attach it to the other terminal of the pigtail using a butt connector. Plug the pigtail into the reg, route the wires out of the way and reinstall the battery.
Attachment 62727
Attachment 62728

Start your truck and make sure it's charging properly. If so then you're done!

Take the money you saved from not buying a new comp, buy a six-pack and another upgrade for your truck!!
Attachment 62729

DOWNSIDE TO THIS MOD__ The only downside is that after doing this, your check engine light will stay on since it has no signal from the alt. There is no way I know of to prevent this, but someone here might have an idea. If that is an issue to you, then this conversion may not be for you!
MY QUESTION IS REGARDING THe PIC WITH THE 4 EYELETS THE 2 IN THE SQUARE ONES ARE TAPED AND NOT USED...DO I NEED TO GET RID OF THE OTHER 2 WIRES ON THE END OR DO I RECONNECT THEM TO THE ALTERNATOR...

I did the repair but did not connect the 2 large wires and it started smoking and I changed them back to the regular black box and it is still smoking... I may be needing a new alternator now either way BUT want to make sure if they still attach or NOT and what to do with them..you have the 2 middle wires with the square tabs taped but not the other 2 with the big wires
 
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Old Apr 27, 2023 | 01:58 AM
  #73  
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Default Pcm/ecu

Originally Posted by vollickvineyards
Having troubles with the download,keeps wanting to download over again when I try to open it.

Suggestions????
Hey just a heads up,I got 3 of them and if you need one I'll do you one for 1/3 of the price. Just thought I'd let you know just in case
 
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Old May 27, 2023 | 11:00 PM
  #74  
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Found this thread via internet search.
What happens with the two exposed wires in the pic?
Are they still used?


 

Last edited by KWPatty; May 28, 2023 at 09:31 AM.
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Old Sep 26, 2025 | 02:21 AM
  #75  
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Default Start with voltage regulator conversion not working and all wiring correct

I need help 2003 4.7
 
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Old Sep 26, 2025 | 08:03 PM
  #76  
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What kind of help? Not sure if this was posted before but a diagram makes it look a lot simpler. What you must do is ID the wires you have going to the alternator. Check this on the vehicle you are working on before doing any work. I would have done this mod differently than the explanation above but the outcome is the same. And I would have used the ASD relay output for the ignition + as this question seems to get asked a lot. Keep in mind this thread is for a first gen but not much changed in later vehicles.


 
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Old Dec 15, 2025 | 06:41 PM
  #77  
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Default Over charging

Originally Posted by psycobilly64
Ok, this is a write up on how to do an external voltage regulator conversion on any and all Chryslers with the reg in the ECM and an unregulated alternator. Till now, if you have charging issues with these trucks you had to replace a $3-500 computer. I did this conversion for $43.28 after sales tax. This can also apply to other trucks if you'd like add a second alt, or the wiring is fried.

Here is a list of parts that will be needed with prices as of 8/3/2011.
Regulator part #
MPI 2VR1 price $13.99
Regulator plug/pigtail part #
BWD PT173 price $8.49
1 coil of 14ga wire $5.99
1 pack of butt connectors $5.99
1 pack of ring terminals $5.99

Attachment 62720

These are the prices and part #s at my local O'Reilly.
Also a couple of self tapping screws.


The first thing you need to do is remove the little plastic box on the back of the alt.
Attachment 62721
Attachment 62722

Tape it up so it won't short out and tuck it out of the way (you will not be using it).
Attachment 62723

Find a good solid place on the firewall or inner fender to mount the regulator. If you don't have a place with a good ground, you can run a ground wire off one of the mounting screws. I mounted mine behind the battery on the metal fenderwell so no need for a ground wire on mine.
Mount the reg using the self tapping screws making sure you have enough room for the plug to stick out from it.

Attachment 62724

Cut two lengths of wire long enough to reach from the alt to the regulator. Crimp a ring connector large enough to fit the bolts the plastic block (removed in step 1) was attached to on to each one. Put them on and tighten the nuts down.
Attachment 62725

Once the wires are connected to the alt, cut a wire long enough to reach from the reg to an ignition pos of your choice. Take one of the wires from the alt (doesn't matter which) and the wire from the ignition pos and crimp them into one end of a butt connector.
Attachment 62726

Take the doubled wire (batt and alt) with the butt conn already attached and connect it to the TOP terminal on the pigtail. Take the other wire from the alt and attach it to the other terminal of the pigtail using a butt connector. Plug the pigtail into the reg, route the wires out of the way and reinstall the battery.
Attachment 62727
Attachment 62728

Start your truck and make sure it's charging properly. If so then you're done!

Take the money you saved from not buying a new comp, buy a six-pack and another upgrade for your truck!!
Attachment 62729

DOWNSIDE TO THIS MOD__ The only downside is that after doing this, your check engine light will stay on since it has no signal from the alt. There is no way I know of to prevent this, but someone here might have an idea. If that is an issue to you, then this conversion may not be for you!


So i tried this and im over charging and i dont know how to get it to stop i have a new alternator and ive tried 2 different regulators with the same outcome
I did this on my 97 ram 1500 5.9
 
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Old Dec 15, 2025 | 07:56 PM
  #78  
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What is it charging at?
 
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Old Dec 15, 2025 | 08:12 PM
  #79  
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Originally Posted by HeyYou
What is it charging at?
When I first start it upper 14s and while driving it's at 15 and when I come to a stop it drops to mid 13s and when I take off it's back up to 15
 
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Old Dec 15, 2025 | 08:35 PM
  #80  
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IS that what the gauge is telling you, or do you have a meter on it, that's actually accurate?? The gauge ain't the best..... And high 14.s is pretty normal when just cruising along.
 
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