Alternator not charging: Getting Hot!

[mbloom65]

1999 dodge 2500 Auto

new batteries

Grid heater deleted

Everything else pretty much stock

 

I replaced my alternator in preparation for getting my ECM rebuild. Installed my rebuilt alternator after they replaced the brushes, diodes and rectifier. 

Started the truck. No charge. Alternator got very hot.

Went and got a brand new alternator.. Same thing.. 

 

I am looking for help!! Where to start trouble shooting. Hoping the PCM isn't fried too! 

 

I am headed to the store tomorrow to buy a new multimeter, mine broke recently, to check the green wire coming off the alternator. Im more worried there is a short somewhere in the wiring.

 

Any help would be appreciated!!!

[cumminsdog]

read here.  

 

[Mopar1973Man]

Yeah. You want to check the blue wire for 12V while the engine is running. Blue wire is the +12V lead.

[Mopar1973Man]

Any updates here?

[JAG1]

Pretty important to check along that whole wire periodically for anything that can cause abrasion or breakage from vibration or constant movement. There is a recent thread about another member finding a problem where the blue wire goes into the top of the plastic connector at the alternator. It looked fine, but on further testing with the VM, he found a weak broken part of the wire right there. He showed a picture with both wires having a very tight bend radius there.

[mbloom65]

Sorry for the delay in posting any updates. It's been a heck of a week. So I checked the blue wire. No luck. It didn't have any voltage. It appears the PCM is not working. I am still new to working on 12V electrical, but have read a lot the past week or two on this issue and the ECM wiring fixes. I ended up having my buddy who is an electrician by trade look at the truck and the wiring schematics and he thought it would be an easy fix for a local computer repair shop to put a new voltage regulating diode in the PCM. 

Also, I have looked at the PCM rebuild through Autocomputerspecialist.com and it is $450... https://autocomputerspecialist.com/shop-now?olsPage=products%2F19985-1999-2000-2001-2002-dodge-ram-cummins-59ltr-pcm-pcm-tcm-tcu-repair-service

and I saw a external voltage regulator from CPPdiesel.com for $80. https://cppdiesel.com/cpp-1805-alternator-regulator-kit-cummins-alternator/

 

Any thoughts on the external voltage regulator or taking the PCM to a local computer shop? 

 

I am already sending my ECM to Autocomputerspecialist next week so if the other ideas are no bueno, i can just bundle them together. 

 

 

 

[Mopar1973Man]

45 minutes ago, mbloom65 said:

Any thoughts on the external voltage regulator or taking the PCM to a local computer shop? 

 

Don't do it...

 

The external regulator will guarantee the battery life will be shorten for sure. The problem is that the location of the external regulator is extremely important. If you mount it somewhere where its too cold it will over-charge and boil the battery dry in a mere few weeks. If you mount it in an area to warm it will under-charge and leave you with a dead battery more often. 

 

You way better off having the PCM sent in and repaired. The battery temperature sensor keeps the batteries at a safe charging voltage and minimize the amount of water lost from the electrolyte. If you want to protect the PCM from this happening again you need to do two mods. 

 

 

Then protect the PCM...

 

I've already been down this road and it cost me a total of $720 to do the repair correctly. Now I've got a 5 amp fuse on the field lead, 150 Amp charge breaker, and fresh alternator that passed AC noise test.

[JAG1]

I would also check the integrity of the pin connector for the blue wire at the PCM as it's not unheard of to have a distorted pin connector.

[mbloom65]

Thanks for the tip JAG1! I will test that connector ASAP.

 

 

Thanks for the reassurance of the right decision Mike. Seems like if its too good to be true it probably is applicable in this instance. I am hoping to put these electrical demons to bed for good! 

 

I have  a new alternator, new batteries and will do the W-T mod and circuit breakers before the ECM and PCM get repaired. 

 

My truck is about to be OOS for a week anyway. I'm putting in the RV275 injectors, an airdog lift pump, new redhead steering box, steering pump and vacuum pump rebuild. So the list keeps getting longer but i am learning something new every day! 

 

Thanks again for all your help. I will update with picture soon. Any other advice or tip will be appreciated

[mbloom65]

So i have exhausted my mechanical aptitude. I seem to be snow balling the problems with my truck. I employed the help of a coworker who is a good diesel mechanic. Long story short... the NEW alternator got fried! After i installed it and ran it (15-20 seconds; just long enough to test the blue wire for 12v) on what I'm figuring is a bad PCM, it won't charge on a good PCM (in a 2002 dodge)!! My friend has the truck at his shop and took the New alternator off my truck and ran it on his wife's old truck, the 02 dodge, and it still got hot and wouldn't charge. Could a bad PCM kill alternators or could it be the build up of electricity since it's not releasing the charge?

[Tractorman]

On ‎1‎/‎16‎/‎2019 at 6:46 PM, mbloom65 said:

1999 dodge 2500 Auto

new batteries

Grid heater deleted

Everything else pretty much stock

 

I replaced my alternator in preparation for getting my ECM rebuild. Installed my rebuilt alternator after they replaced the brushes, diodes and rectifier. 

Started the truck. No charge. Alternator got very hot.

Went and got a brand new alternator.. Same thing..

 

When I read your original post, I am assuming the first alternator you removed was still working because you said, "replaced my alternator in preparation for getting my ECM rebuild".  You didn't say, "replaced my alternator because it wasn't working". 

 

It would be valuable information for the readers to know whether or not your original alternator was still working. 

 

- John

[mbloom65]

yes. Still charging, but the brushes were almost completely wore out. While i had it out and apart, i had the shop install new diodes and a new rectifier. 

 

It also worth noting that i did experience some of the other electrical problems sporadically i.e. weird vibration at 55mph.(installed BD diesel noise isolator) and sporadic APPS problems 

[Mopar1973Man]

2 hours ago, mbloom65 said:

t also worth noting that i did experience some of the other electrical problems sporadically i.e. weird vibration at 55mph.(installed BD diesel noise isolator) and sporadic APPS problems 

 

I highly suggest you un-do the noise filter mod. Creates bigger problems with masking the problem and you'll end up eating ECM's and VP44's.

[JAG1]

I believe there are some external voltage regulators that have temperature sensing ability. They range in price, I'm guessing, 300 to 500 hundred bucks, ouch and designed for boats at sea, for the marine environment.

 

mbloom65, take it slow, figure out the charge problem having the alt put on a test stand. I wouldn't test a suspect alt. on another rig for risk of ruining something on the other truck

 

Did you read the article about the bad grounding the alternator has thru its mounting bracket and bolt. I corrodes bad inside the tightened surfaces i.e. bolts, mounting bracket engine block all get rusty in there. It is generally a bad ground by now with so many years on its existence. I ran my own ground from alt casing to passenger battery neg. post for added insurance.

Edited January 23, 2019 by JAG1

[Tractorman]

@mbloom65, I would be looking for something that might have happened when you changed out the original alternator, since it was working fine.  Something as simple as a poor ground like @JAG1 suggests or something else that is being overlooked could cause the problems you are experiencing.

 

If the truck were mine I think I would rig up a complete separate temporary circuit with either a fixed resister or a variable resistor and 5 amp fuse protection to the field control circuit of the alternator.  This way I could prove whether or not the alternator is working properly without risk of damaging the PCM.

 

- John

 

Edited January 23, 2019 by Tractorman
more information

[Mopar1973Man]

Even easier yet. Remove the alternator have it bench test for performance. Replace if it fails or marginal...

[Tractorman]

16 minutes ago, Mopar1973Man said:

Even easier yet. Remove the alternator have it bench test for performance

 

In this particular case I think all of his alternators would have bench tested fine.  He needs to know why they aren't working on his truck.  That is why I would go to the extent of making a separate field control circuit.

 

- John

[Mopar1973Man]

So...

 

Need to test the green and blue field leads quick. 

 

BLUE field lead - Just unplug from the rear of the alternator and start the engine. Red Probe goes to blue wire and Black Probe to battery NEG. This should show battery voltage only while running. Key ON, Engine OFF there should be no voltage present.

 

GREEN field lead - With it still unplugged and engine running. Red Probe to the battery POS and the Black Probe to the green wire. This should show battery voltage while running. Key ON, Engine OFF there should be no voltage present.

 

Black Charge Lead - Should show battery voltage without the key on or engine running. If not the 140 Amp fuse blew. 

 

Edited January 23, 2019 by Mopar1973Man

[Dieselfuture]

18 hours ago, mbloom65 said:

Long story short... the NEW alternator got fried!

Where is it from,  parts store? It can be junk new, I'd get an original denso one online or nations for more money. Put your original rebuilt one on and do the 5amp fuse mode like @Tractorman mentioned and see what happens. If you didn't change brushes and/or armature, there will be some extra ac noise. 

[dieseljames]

What ended up fixing this issue for you?