I'm sure you guys are sick of this but ya, I'm starting another alternator thread. I've read a whole bunch but, as usual, they are full of conjecture and suggestions and maybe a solution but not much in the way of hard data.

I replaced ALL of the fusible links on my truck with MTI Midi fuse holders and I am still having problems. My alternator keeps blowing and melting 125A and 150A fuses. It's an issue. I also have the pulsing light issue and now I think my alternator is dead. Super annoying. I just replaced my alternator and battery a year or so ago and my volt meter in the cab has always been unreliable. It would only read about 12v+ volts but a multimeter on the battery and alternator would show the typical 13v+

**Side note, do not use the MTI MidiVal holders. They are italian euro parts which are poorly supported and hard to obtain. Since this installation Eaton/Bussmann has stolen the idea from MTI and released their LMI line of Midi fuse holders with way more support and part availability so I get the joy of spending another $200 and fixing the same problem for the second time**

So, as I understand it, these trucks run 120A alternators with an external voltage regulator that may, or may not, be part of the ECU. It seems like an alternator upgrade (higher amperage) is not easy so I'm just going to stick with the 120A for now.

What are people running for voltage regulators? I have heard of people running a $25 Transpo 8315 regulator that you can install directly to the alternator but apparently they are junk and will then blow everything in your truck. Is there a super reliable, high quality voltage regulator I can install? Or is it better to install a 1 wire alternator and do away with all of the external regulator crap?

I'm going to install an eaton/bussmann MRBF (Marine Rated Battery Fuse) to the positive terminal. It's a nice unit with 2 studs/fuses. I'll use one for a direct connection to the alternator and the other can run the Midi fuses which replace the fusible links. I want to eliminate all dodge wiring as it relates to the alternator and battery. Everything else in the truck works fine.

 

I was having a overcharging issue and spent forever chasing my tail. Ended up being the new napa voltage regulator i installed. It was causing me to get 15+ volts from the alt to the batt. I replaced it with a oem regulator i got from the dealership cost an arm n a leg... think bout 90$ if i remember correctly. Haven't had a problem since.

Hope you figure out whatever is causing your issue.

 

Seems like a common denominator is the voltage regulator and/or insufficient grounding. It appears that when it comes to VRs you get what you pay for. Some say MOPAR only.

My problems have all been poor grounding or bad wires.

If POs have screwed around adding wires/accessories or "fixed" things then the problem is compounded...

 

Ya, I'm just looking to omit the garbage completely but I don't want an ebay/amazon voltage regulator. I would like something good quality aftermarket. I don't think OEM/Dodge qualifies as good quality.

 

I wasted a lot of time and money on this problem. Save yourself some grief and spend the $$$ on a one wire alternator.

 

Is there any consensus on which one wire alternator is the best quality and easiest to install? I have the added complication of being in Mexico so I don't know how easy it would be to get a PA Performance unit.

 

This is the one I got DODGE CUMMINS ONE WIRE ALTERNATOR - 8902SE (heielectric.com). It is a direct bolt in with simple instructions. And they do international shipping. The only catchs I encountered in the installation is I had to relocate my transmission coolant lines slightly to clear the back of the alternator and I couldn't use my battery isolator..

 

Not trying to rain on everyone's parade at all but the one wire alternators also use a voltage regulator its just attached to the alt. So in theory wouldn't those also good bad after x amount of years or usage?

I can't really say the oem dodge voltage regulators are trash when it lasted 30 something years and the new ones been working fine for the last few years.
I have heard someone say they get them from the junk yard and keep a few in the truck for when it fails. Thats using old used parts though and also if your trucks still ruining voltage regulators often its probably something else not the regulator. The napa one I bought was trash from the get go.

 

Alot of times you are no longer getting true battery voltage from the keyed hot to the voltage regulator. Putting a relay in to feed the voltage reg with true battery voltage will help, there are a few writeups in here on that

 

Jim Lane (you still out there Jim?) was always proud of his Leece Neville alternator and is an excellent source of info for anything electrical:
FAQ/Knowledge base "How do I...?" Look here first! A.K.A. "The Sticky" - Dodge Diesel - Diesel Truck Resource Forums
https://www.dieseltruckresource.com/...s-t247286.html
https://www.dieseltruckresource.com/forums/alternator-101-t307266.html
Alternator Ground - Dodge Diesel - Diesel Truck Resource Forums

 

Good to know. Why couldn't you use your battery isolator? Also, not crazy about rerouting lines.

Yes, you are correct but you may be able to get an alternator with a more reliable voltage regulator.... I'm not sure.

The Dodge voltage regulator is on the main circuit board inside the ECM so you can't easily swap it out. Any of the aftermarket companies are almost certainly getting the voltage regs made in china so they are probably all equally junk. When the voltage reg goes your truck is gonna get cooked. It's a pretty important bit of kit.

That Leece Neville install is interesting but a lot of work and possibly unnecessary for me. Don't think I need that much amperage. I don't really feel like doing all of those mods to make it work.

 

Not really in need of this, but am following it as matter of interest. Would Rock Auto have a suitable replacement? They ship to Mexico.

 

What ecm are you referring to? Pretty sure my truck doesnt have one. The pcm/ecm werent introduced till the 91.5 model year (supposedly thats hit and miss depending on the truck) The stock location for my trucks VR is on the fire wall. I have heard the 92 model year has a VR in the pcm but not certain if thats true or not. The dodge oem VR that i got was made in USA If i remember correctly but you are right most aftermarket parts are made in china these days as cheaply as possible.

What year truck do you have? could you fill out your signature so we know?

Im really lucky when my VR went out and that nothing got fried. It was getting up to 18v and resting at 15v at the battery. My headlights got ALOT brighter and my battery started boiling. Other than that Ive looked it over a ton in the years since and havent found any damage to wiring ect.

 

I wouldn't trust it... Overcharging a system can be bad and id rather be safe than sorry. Yeah you can save 60-80$ but is the possibilty of this headache/ possible damage to truck worth it?

 

Nah, it'll all be aftermarket, mystery source crap.

Oh, I guess that could be a thing. my truck is a 93. It has one of these:


^^This