Engine/Transmission (1994 - 1998) Alternator and Charging issues 95 12Valve

[JDrummond]

Long time listener, First time caller.



(Some of you will know how old I am by that statement)



Ok,

The truck is a 1995 X-cab 2500 with an auto. 12 Valve of course. The truck sat for 13 months prior to my friend purchasing it. The truck had guage problems, OD would not shift on/off and alot of other small things wrong.



PROBLEMS FIXED:

Got the guages repaired by tracing a broken connector inside the ignition wiring loom.



Put two new batteries in to replace the two 12 year old stock jobbers.



OD was fixed when the ignition wire was repaired and a new connector securely attached.



NOW, here is the fun part!



The Alternator was charging last night. This morning NO CHARGING.



Check Engine light is on and the code reads "charging circuit open"



The alternator was jumpered with leads directly from the battery to test the charging of the alternator itself. Not the circuit. The alternator failed. No problem, new alternator. Right!?



Wrong.



Tested the alternator and it is 100% in the green. The drop out switch tested positive when on the Modus and could be activated manually. Alternator still won't give off a charge.



NOW. I need some one who has had a similar problem with their alternator or charging system to give me a damned good reason why it isn't working.



All grounds have been cleaned and new ends placed on the truck. This dude is so anal about how clean his engine compartment is I think he is a serial killer. I don't see anything else that is obviously wrong.



Need some specific area to look at on this charging system before I commit to another weekend of flat beer and cheeto's sitting on my butt wondering what is wrong.



HELP PLEASE ! :{

 

[wildmanben]

Does the tach work? check the crank sensor.

 

[JDrummond]

Tach works great. Still having an issue with the OD but i am certian it is voltage related.



The CPS is in great condition. We swopped it onto my 95 to see if it was dead. In fact, most of the components replaced on his truck were originally taken and tested on my truck to ensure failure or operational status.



Without changing my entire electrical system into his truck I am looking for a better way to diagnose the problem.

 

[JFaughn]

It sounds like your test on the truck had issues [ wrong ] , the bench test seemed to confirm that .
Then I am not following your terminology is off , at least to me ,[ drop out sw. -?, modus -? , ]
these are not terms I've heard when working on charging systems .
If I knew what you were refuring to , I could have a suggestion .
The regulator for the alt. is in the computer , and almost never goes bad , 2 comin things that these charging systems have failures with seem to be the brush [ not in your case , maybe , since it bench tested good ] next the connections , maybe the fusible links at the drivers side battery .

 

[dclassens]

MODIS is a new(kinda) Snap-On scan tool that does amazing stuff. It sounds like he was using this scan tool to do function tests on certan parts of this truck. MODIS stands for MODIS-Modular Diagnostic Information System. check it out here:



http://buy1.snapon.com/catalog/item...group_ID=17428&store=snapon-store&dir=catalog



Dave

 

[Missouri Mule]

Did you check the fuse insisde the PDC ( should be fuse labeled alternator or charging system). If it is blown you will have to find out why it blew.

 

[CToney]

You can wire up an old style Dodge voltage regulator to get you by until you find the problem.

 

[RVPILOT]

alternator

I have many miles on my 96 and have experienced about everything that can go wrong. My alt quit working yesterday, My fitfth one, this time I found out it was one of the batteries compleatley dead. A Wall Mart Everstart.

I believe I am onto something about alt failures, that is when one batt starts to fail it puts a extra load on the good one and causes the alt to work harder

so when I go to exchange the failed battery I get a replacement, now I got a new battery and an old one and the cycle starts all over again, that is premuture failure of the new battery and alternator. replacing the brushes usually works as the bearing are still good. today I will get two new batteries not Walley's World stuff. I also noticed my turbo has a little play in the bearings, any suggeations ? Stormy

 

[RVPILOT]

Alternator and battery failure

This is a follow up to earlier post. went to Wall Mart to exchange Batteries and they agreed with me about having different ages batteries in the circuit

so they replace both even the one that was only 5 months old. so my theory was right . when replacing batteries replace both as you ae not cheating Wall Mart just yourself. Stormy

 

[Howard Durand]

The generator field is supplied by a 30 amp fusible link or fuse in the PDC and feeds through the ASD (automatic shutdown) relay.

The ground leg of the field circuit is controlled by the PCM at pin 20, dark green wire.

There could be a problem in the ASD circuit or in the wiring between the generator field terminal and the PCM.

This is correct for the 94 which should be the same in the 95.

 

[JDrummond]

All Better ! ! !

Many usable suggestions and all greatly appreciated. YES I AM A POOR SPELLER. I appologize for the incorrect spelling of M O D I S.



I have been talking with several local mechanics and they all have suggested a bad resistor somewhere in the harness.



News to me but, okay I will be appreciative of just about any suggestions at this point.



All of the battery cables have been repaired or replaced. The fuasbale liks were corroded about 1/2 inch into the circuit. I replaced the connector and the link seems okay but it is hard to tell with the alternator not charging.









DING DING DING ! We have a winner.



Howard Durand!



Pin 20 it is Howie! No ground to activate the charging field.



PCM getting replaced as we speak. I Greatly appreciate the assistance Lads.



More to come I a certian. :{



After all . . . . . . . IT'S A DODGE !:-laf

 

[tgrfan2]

My 95 did the same thing one morning. I tapped on the alternator in several areas until it started charging again. I assume it was a stuck brush. That worked for about 3K and it did it again . Then I had the alt rebuilt.
If a small hammer doesn't work, get a bigger hammer!!!!

 

[dcgere2]

Im in need of some help please .... I have an unmolested 95 12 valve Dodge 2500 Cummins diesel and the problem I'm having is its not charging I change the alternator checked all the wiring thanks to the threads here on this website and I did not find no break in the wiring whatsoever or any bare spots the one thing that I did find is that 30 amp fuse was blown I replaced it and it blew as soon as I turn the ignition on so then I searched through the wiring and found no damage to it anywhere or corrosion of obvious so I took a jumper wire went across started it I was holding 14 volts a steady 14 volts but then I put another fuse on it and took off the jumper wire and it held I shut the truck off and then went to start it again and that fuse blew is it possible that the warming coil for starting is shorting out and causing it to pop that fuse on initial ignition
Thanks for any help David in mid michigan

 

[dieselguy12]

it might be your voltage regulator those are a common problem for the 12v

 

[dieselguy12]

it might be the voltage regluator they are common problem to have on the 12vs

 

[Jfondren]

I also have a problem with charging issues. I got a 1998 3500 5.9 cummins. Checked both batteries they checked good. They say alternator is good when it's checked. When you start it it charges about 12 volts drive or let it idle for about 15 minutes it drops to zero and it will die. Which I still think it's the alternator because once it runs the batteries dead it dies. Once it dies you have to jump it. Any suggestions would be greatly appreciated. Thanks in advance!

 

[Tractorat]

Im not a mechanic. But Im pretty sure that if you're only seeing 12 volts when its running, you are only seeing the battery voltage. I dont think the alternator is working at all. I would get a second opinion

 

[Jfondren]

Im not a mechanic. But Im pretty sure that if you're only seeing 12 volts when its running, you are only seeing the battery voltage. I dont think the alternator is working at all. I would get a second opinion

Thanks for your response I had it checked again it was good. So I decided to just buy a new one and it solved the problem.

 

[fest3er]

I had my original alternator rebuilt locally back in December. It only lasted 18 years. It only put out partial charge (one or two soft diodes, and several of them showed signs of bluing--extreme heat) and it had an internal part that was just about worn through (and a real pita to replace). Couple weeks later, I bought a rebuilt starter from them. Original was 18 years old and I'd replaced the contacts and solenoid once; it no longer turned the engine over fast enough to ignite the fuel. At that age, I figger parts really don't owe me much. (And probably not charging the Optima red-tops properly may have shortened their life a little; I only got 14 years out of them.)

When an alternator charges but stops charging after it gets significantly hotter, you can almost guarantee that diodes have gone soft, heat-wise, and are preventing proper current/voltage generation when hot. (Diodes can become more heat-sensitive over time.)

If it was charging, then suddenly stopped, always check the 140A fuse in the PDC (underhood fusebox) first. Shorting the B+ terminal at the alternator can blow the fuse.

 

[Missouri Mule]

Should have relay in the pdc check it out