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Discussion Starter · #1 ·
I have a 1998(.5) Ram 2500 24V Diesel. I haven't had a problem with the electrical system in the 5 months I've had it. Driving around tonight I saw the check gauges light go off and the volt meter on the dash was down at like 10 volts (it's normally up around 13). I had to run into where I was going so parked and disconnected the batteries (cause that seemed like a good idea?). When I got back it wouldn't turn over. I got a jump and got it started. Drove it back to the house and the volt meter started at 10 and then just kept dropping to as low as it would go. The headlights and dash lights were barely visible, but it ran fine.

I'm a newbie so don't really know what's going on, but does this sound like the alternator? Or something else? If it's the alternator is it better to get a new one or try to rebuild the current one? Any help is greatly appreciated.
 

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Yes sound liek alt but could be a shorted batery too. But I think alt because when running alt should put out 14v. Pull alt and batteries and have them load and bench tested at a parts store. Do this after cleaning and checking all battery terminals to a shiny metal connection. A broken ground connection there could also do it.
 
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Discussion Starter · #3 ·
Some additional info I probably should have added. The batteries were tested and fine about a month ago. I rotated their position and cleaned off the terminals well at that time. As I thought about it, I did accidentally spray a not huge amount of water on top of the engine area last weekend when I was flushing the heater box, but had driven it a few times since then and hadn't noticed any problems. Don't know if that could have led to a problem.
 

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Sorry but how things were a month ago means nothing. But if that is the case you should start by pulling the alt and have it bench tested at the store. It is free.
Hosing it down should not have hurt anything.
 

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All vehicles, regardless of make, have electrical problems, eventually. And most electrical problems,12v, are grounds, for various reasons.

After checking the "usual suspects", IE: battery/alternator, start checking the grounds.
You're going to need a service manual.
 

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ESp the grounds on a dodge .
 

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Discussion Starter · #7 ·
Update: I put both batteries on a charger and they took and held a charge. I had them and the alternator bench tested at 2 different auto stores. Both stores said everything was working fine. I checked the continuity on all relays and fuses (on the whole vehicle) with a multimeter. I then checked all the grounds and they seem to be fine although I'm going to re-check that as I'm not 100% that I did it all right.

Any other suggestions on what might be going on? I haven't hooked the batteries back up and started it to test different voltage while running because I'm worried that if something drains the batteries out again it might kill them. I'm a newbie so maybe this isn't a legitimate worry. When thinking about it I did re-wrap the wire that can cause noise interference with the auto transmission with aluminum foil and put a new loom on it, but I double checked it today to make sure it was all covered and the connections looked in good shape. As always, any help is greatly appreciated!
 

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You actually have to test for a parasitic draw if the problem persists.

testing batteries is a crap shoot unless the person testing is smarter than the batteries.
One bad battery kills both batteries.
 

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What was the voltage on the alt during the bench test? Maybe just bad battery terminal pr cable. maybe pcm ois bad and not regulating charge. There is also a batter temp sensor under the driver side battery, but I do not know its symptoms exactly.
 

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Discussion Starter · #10 ·
As best as I've been able to figure out the problem is in the alternator. There isn't a parasitic draw and I Voltage Drop tested all the grounds and connections and everything is fine. The alternator is putting out about 13.5 V and keeps the batteries charged if no additional load is on, but if I use lights, etc. it drops and slowly drains out the battery. It could be the PCM, but I'm not sure how to know that for sure. I discovered in all this that the alternator isn't the right one for the truck so I'm going to get a new alternator and then go from there to see if that fixes it. I just made a new post with the following questions about a new alternator if anyone has any input. Thanks again for all your help! I can't tell you how much I appreciate it.

I've got a 1998(.5) Ram 2500 24V Diesel. The alternator is only putting out 13.5 V (rated at 120 A) and is causing some problems. Battery drain, etc. I have discovered that it isn't the correct alternator for this truck. So, I'm planning on getting a new/re-manufactured one. My questions are:
1. What is the best brand/model to get and best place to purchase it?
2. Does it make sense to get a larger sized alternator than stock as long as I'm replacing it? I live in a pretty warm place and am running a few led aux lights, etc, but no major electrical add ons. If so, what size would make sense to get?
 

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Discussion Starter · #11 ·
I've got a 1998(.5) Ram 2500 24V Diesel. The alternator is only putting out 13.5 V (rated at 120 A) and is causing some problems. Battery drain, etc. I have discovered that it isn't the correct alternator for this truck. So, I'm planning on getting a new/re-manufactured one. My questions are:
1. What is the best brand/model to get and best place to purchase it?
2. Does it make sense to get a larger sized alternator than stock as long as I'm replacing it? I live in a pretty warm place and am running a few led aux lights, etc, but no major electrical add ons. If so, what size would make sense to get?

Any help is greatly appreciated!
 

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You can spend extra onaftermarkey alternators if you like, but not really necessary. The stock 136 amp is fine, I prefer the Bosch version if you can find one. It is better than the Nippon Denso versions and has less high AC issues. Avoid Napa nippin and Napa versions. Does your have small screw type connections or the plug on the small wires?
 

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Lors of missing info-
any alternator you buy from the chineease parts stores are sort of rebuilt
usually they replace the brushes and bearings and call it rebuilt.-plus paint
The better new ones pumping way over 200 over amps are great cause they are new,
and as in my case with a snow plow the extra amps are a great thing!
So if you have extras on board like a winch you might consider
Next - buying ANYTHING off eBay or amazon is highly dubious because of the
high percentage of counterfeit parts.
BTDT
 
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