Archived 98.5 24 valve, no alternator, not charging, Alaska

[JFleishman]

I have a 98. 5 dodge ram 2500 with the 24 valve, auto transmission 4x4.

All data gathered while engine was running,

I am having an issue with the alternator not charging, the problem came up when I was driving to town the other day and noticed that the voltmeter was reading below normal, when I got to my shop I threw a voltmeter on and I was getting 12V or less. I was also having issues with the transmission, it felt as if it were stuck in 3rd gear.

I replaced the alternator with no change, truck still not charging.

I tested the to see if I had voltage at the two small terminals on the alternator, I was not getting any readings, I tried connecting each terminal to a 12V voltage and I did not get any increase in the output which hovered around 12. 0-12. 5V

where do I go from here? is there an possible ECM issue and I need to convert to external regulated? is there a fuse that could have blown?

Truck is dead in the water

Please note: if you respond to "just search TDR there are lots of post about this" please provide a link(s) to said resources. I have searched already and now I am asking for help.

Thanks in advance

 

[HBarlow]

You didn't provide needed information such as odometer miles, battery and alternator service history, etc.

If the truck has high mileage as a '98 probably does you probably have an alternator with worn brushes.

I have been successful in having a small Amish shop in Indiana rebuild two alternators for me. I strongly prefer a quality rebuild of my own alternator by an honest and experienced shop over a cheap auto parts store "rebuillt alternator" with a warranty of questionable value.

If your replacement alternator is a good one you could have battery problems. You didn't provide info on your batteries so that is only a possibility to consider.

A good repair shop or even a SAM's Club, Wal-Mart, or Autozone should be able to hook up a tester and tell you in a minute if your problem is caused by alternator, batteries, or other.

Some of the older trucks have developed corroded ground connections which create mysterious electrical problems.

 

[JR]

Check the fusible link in the fuse panel on the driverside wheel well. If thats good, visually inspect all ground cables, make sure all connections are clean and tight and make sure theres no broken cables. Then you need to have your batteries load tested, they would have to be in bad shape but it is possible if theyve got enough dead cells they wont take a charge. It only takes running them dead once to kill em, especially if the acid level is down. If you still cant find anything, its most likely the pcm it controls the charging.

 

[GAmes]

The PCM failing is a last resort, there are several things that shut off the alternator. The first thing I thought of is the main fuse in the power box under the hood. On mine it is a 140 amp and has the positive lead from the drivers side battery going to one end. When mine failed it LOOKED good, but was broken internally. Check it with a multimeter. Here is one link that might help.

https://www.turbodieselregister.com...ECM-or-Cam-Position-Sensor&highlight=charging



The other thing I thought of is the cam position sensor, but you didn't mention a CEL or a tach failure.

 

[Bob4x4]

I used to see many 24v with a blown fuse,many times right after an oil change. The filter wrench can short at tha alternator batt connection

 

[JFleishman]

Thank you all for all the input, Here is some additional information and an update to the status,

218,000 miles

Batteries, Replaced November 2011, Diehard platinum (AGM). Alternator replaced October 2011 and Jan 14 2013.

No CEL's I will check for pending codes tomorrow.

Visually inspected grounds, they look decent,
Checked continuity on grounds to various locations on engine/alternator, continuity present

Fusible link OK, checked continuity and voltage to ground on both sides of the fuse and there is voltage and continuity.

I have some other things to check having to do with some car audio work,


While the truck is down I have it rough, driving a 2012 Ram 2500 (Hemi) with 800 miles on it, makes want the newer truck every day, but the 98 is mine and paid for.

Thanks again,

 

[Bob4x4]

I have a 98. 5 dodge ram 2500 with the 24 valve, auto transmission 4x4.

All data gathered while engine was running,

I am having an issue with the alternator not charging, the problem came up when I was driving to town the other day and noticed that the voltmeter was reading below normal, when I got to my shop I threw a voltmeter on and I was getting 12V or less. I was also having issues with the transmission, it felt as if it were stuck in 3rd gear.

I replaced the alternator with no change, truck still not charging.

I tested the to see if I had voltage at the two small terminals on the alternator, I was not getting any readings, I tried connecting each terminal to a 12V voltage and I did not get any increase in the output which hovered around 12. 0-12. 5V

where do I go from here? is there an possible ECM issue and I need to convert to external regulated? is there a fuse that could have blown?

Truck is dead in the water

Please note: if you respond to "just search TDR there are lots of post about this" please provide a link(s) to said resources. I have searched already and now I am asking for help.

Thanks in advance

Sending B+ to the pcm alt control ckt was not a good idea.
The alt output-large black wire should be B+ not to be confused with the black ground wire
The green wire should be the regulator(pcm control) a varying ground
The other field wire will be B+ white with black

 

[JFleishman]

Update,

The truck has been parked at work and it has been a bit of a time scheduling ordeal to have enough time to mess with it.

I did wire in a external voltage regulator for the alternator so that I could drive it home and work on it further there.

i used a mid 70's voltage regulator from a dodge truck BWD R296, it works and it allowed me to drive home with lights and power as the sun was setting.
Here were some helpful links in the implementation of the fix:

https://www.turbodieselregister.com...Voltage-Regulator&highlight=alternator wiring
http://alternatorparts.com/external-voltage-regulator-high-output-alternator-kit.html

I still have a transmission problem, it acts like it is stuck in 3rd gear all the time, when it is in (D). I can manually shift it to 1,2 and get moving form the stop lights better. When I get to 45mph the tach reads 2000rpm, I am wondering if I pulled a wire loose under the dash when I was working on the radio last week. One day it was fine, the next day it was not.

Thanks for your feed back everyone,

 

[JR]

The "scheduling ordeal" doesnt have anything to do with the fact your cruising a 2012 around while yours is down does it?

Trans. functions are monitored by the pcm on the pass side firewall, hopefully no damage was incurred by your alt tests

 

[JFleishman]

I don't think the alternator tests had anything to do with the Transmission not shifting, that problem cropped up at the same time of the alternator issue surfaced, not after repairs.

Yes cruising in the 2012 has spoiled me, But getting home to play with 3 little kids and other commitments keeps me in a state of constant motion.

 

[JR]

Ok well theres 2 functions controlled by the pcm that are not functioning (charging and trans) too bad you couldnt come up with a donor to temporarily swap just to see if it cures what ails ya. I dont know of any ways of testing them so swapping is probably the only way to find out.

 

[Shamp]

9 day old thread but i thought id mention it for future reference. One of the fastest and easiest ways to test an alternater is the check continuity with a multimeter between the pos post on the alt and the alt caseing. If it has continuity then the alternator is bad. And the first thing to do in any chargeing problem is the clean battery cables. There is no such thing as they look good. Take them off and use a battery terminal cleaner. The blade type work best. Clean any other cable connecters with sand paper. You can even smear a little De-ox on it afterwards. De-ox is basically a grease to keep electrical connections from carroding. Dielectric grease i think is is another name for it.

second thing is the acronym "KISS" Keep It Simple, Stupid. I not saying it isnt, but with a no charge situation the first step is not replaceing computers. Basics first

These things may not be helpful to you but maybe someone in the future can refer to it.

 

[KB0OU]

It sounds to me like the stereo work may have caused the problem. You may have disconnected a input to the PCM,,, maybe speed input or something like that.

The PCM controlls the Battery Charge, the Transmission, and the Dash Functions on that truck.

If you disconnected something behind the dash it could have shut down the PCM functions.

I am surprised the Dash is functioning though, so it may be something else.....



Good Luck. .