Alternator / voltage regulator - Dodge Cummins Diesel Forum
- HOME - FORUMS - GARAGE - TECH - ARTICLES - CHAT - CLASSIFIEDS - REVIEWS - VIDEOS - MEMBER MAP - STORE - INSURANCE -
- REGISTER - CALENDAR - INFO - SITE HELP - RULES - STAFF - MEMBERSHIP - ADVERTISE - CONTACT US -


Welcome to the Dodge Cummins Diesel Forum, the fastest growing Dodge Diesel Community on the internet.

You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please contact contact us
Go Back   Dodge Cummins Diesel Forum > 2nd Gen. Dodge Cummins 94-98 12V Forums > 94-98 Non-Powertrain
94-98 Non-Powertrain Discussion of 94-98 Topics Not related to the Powertrain...NO ADVERTISING

CumminsForum.com is the premier Dodge Diesel Truck Forum on the internet. Registered Users do not see the above ads.

Auto Insurance

» Featured Product
Wheel & Tire Center

Reply
 
LinkBack Thread Tools Display Modes
Old 01-22-2007, 07:58 PM   #1 (permalink)
Cummins Fan
 
butt6767's Avatar
 
Join Date: Jan 2007
Location: NEVERSINK NY
Posts: 59
Thanks: 0
Thanked 0 Times in 0 Posts
iTrader Score: 0 reviews
Alternator / voltage regulator

Hi my 96 amp metor gauge is about at 12.5 volts until I get up to 55mph. What I would like to no is there a voltage regulator, or is it built into the alternator. thanks
butt6767 is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 01-22-2007, 08:22 PM   #2 (permalink)
Super Moderator
 
Join Date: Nov 2005
Location: Montana
Posts: 16,214
Thanks: 27
Thanked 2,120 Times in 1,573 Posts
iTrader Score: 0 reviews
The regulator is built into the PCM (computer) and costs $500 plus to replace.

Once you are certain the problem isn't the alternator or batteries you can disconnect the PCM regulator and use an external one. It's easy, cheap and won't effect anything else. Any 12 volt regulator will work. Remove and tape the small wires on the alt replace as in the picture below. Make certain the switched positive is at the top of triangular connector, the other two wires are interchangeable. The regulator doesn't have to be like the one below, in fact the number on it is no good.
Attached Thumbnails
Alternator / voltage regulator-17307regulator2.jpg  
__________________
Bill
'95 2500 4wd auto
'95 3500 5 speed heavy hauler
Stock for one day
illflem is offline   Reply With Quote Quick reply to this message
The Following 2 Users Say Thank You to illflem For This Useful Post:
Hit.It. (04-26-2010), mjgcamper (04-25-2010)
Old 01-22-2007, 08:34 PM   #3 (permalink)
Cummins Fan
 
butt6767's Avatar
 
Join Date: Jan 2007
Location: NEVERSINK NY
Posts: 59
Thanks: 0
Thanked 0 Times in 0 Posts
iTrader Score: 0 reviews
How can I test the alternator? Or should I bring it to an AutoZone or somewhere like that.
butt6767 is offline   Reply With Quote Quick reply to this message
Old 01-22-2007, 08:37 PM   #4 (permalink)
ISX
Diesel Freak
 
ISX's Avatar
 
Join Date: Mar 2006
Location: Missouri
Posts: 843
Thanks: 1
Thanked 11 Times in 8 Posts
iTrader Score: 0 reviews
Start your truck, then disconnect both batteries, if all your lights and everything still work and the truck still runs, alternator is doing its job, if not, the alternator isn't doing anything or you have a bad connection..

Another way gauranteeing its the alternator is with a voltometer. Hook it to the batteries when its not running and it should be around 12V, when you start it up you should be up to around 14Volts. If not, then its the alternator, but I would run through all the wires and make sure they aren't corroded or anything and that everything is getting a connection...
__________________
1990 F250 7.3 IDI NA auto 4x4 250k
1997 2500 12V Cummins 5spd 2wd 322k miles #100 plate, SB Con O, 26.6MPG-55mph

Last edited by ISX; 01-22-2007 at 08:44 PM.
ISX is offline   Reply With Quote Quick reply to this message
Old 01-22-2007, 08:41 PM   #5 (permalink)
Cummins Fan
 
butt6767's Avatar
 
Join Date: Jan 2007
Location: NEVERSINK NY
Posts: 59
Thanks: 0
Thanked 0 Times in 0 Posts
iTrader Score: 0 reviews
Great tip ISX will get on that first thing in the morning
butt6767 is offline   Reply With Quote Quick reply to this message
Old 01-23-2007, 08:14 AM   #6 (permalink)
Cummins Fan
 
butt6767's Avatar
 
Join Date: Jan 2007
Location: NEVERSINK NY
Posts: 59
Thanks: 0
Thanked 0 Times in 0 Posts
iTrader Score: 0 reviews
wll i disconneted the batteries and the truck died . looks like i need a alternator.
butt6767 is offline   Reply With Quote Quick reply to this message
Old 01-23-2007, 08:46 AM   #7 (permalink)
Diesel Freak
 
got...DIESEL?'s Avatar
 
Join Date: Jan 2006
Location: Panama City (Lynn Haven), FL
Posts: 768
Thanks: 0
Thanked 33 Times in 11 Posts
iTrader Score: 0 reviews
Don't be so sure. The alternator is just the slave, without the PCM to make it charge it sits cold. Unhook the two small field wires located on the back of the alternator attached with 8mm nuts. Keep them away from grounding on the block etc. Attach two jumper wires, polarity doesn't matter...one to each stud, then the other ends to positive and the other to negative. This will full field the alternator and bypass the regulator. I wouldn't hook up the jumpers until the truck is running. It will display full output so don't leave it that way but for a couple of seconds. Voltage can go sky high by full fielding. Once you have done this, leave the truck running and using a voltmeter check for voltage acrosss the terminals you took off. One wire is pos and the other neg, you should see between 7-12 volts. This will tell you the PCM is supplying field voltage and current to the alternator. In which case keep looking. If the alternator didn't labor the engine, or show high voltage on a meter, it is most likely short on brushes. If it did, well keep looking again.

I wouldn't go throwing an alternator at it until you've diagnosed it down a little further. Taking off the batt cables is not a good thing to do to modern charging systems, and it still doesn't tell you the problem with the charging system.

GL
Chris
__________________
In NW Florida? Get a hold of me...it's time Dodge makes it statement in these parts!!

'95 2500 Std Cab 4X4...
DTT billet trans and billet triple disc, billet flexplate, compound turbos, AEM Dryflow, 160 pump, custom plate, 191's, EDM370's, peaked and tweaked AFC, rack control plug, 20*, 3K, head studs, marine +.020 HG, Water/meth

got...DIESEL? is offline   Reply With Quote Quick reply to this message
Old 01-23-2007, 09:42 AM   #8 (permalink)
Cummins Fan
 
butt6767's Avatar
 
Join Date: Jan 2007
Location: NEVERSINK NY
Posts: 59
Thanks: 0
Thanked 0 Times in 0 Posts
iTrader Score: 0 reviews
ok i will try this thanks gl
butt6767 is offline   Reply With Quote Quick reply to this message
Old 01-23-2007, 07:04 PM   #9 (permalink)
Cummins Fan
 
butt6767's Avatar
 
Join Date: Jan 2007
Location: NEVERSINK NY
Posts: 59
Thanks: 0
Thanked 0 Times in 0 Posts
iTrader Score: 0 reviews
i got 12.24 volts across the 2 wires i guess it is the alternator
butt6767 is offline   Reply With Quote Quick reply to this message
Old 05-25-2009, 03:33 PM   #10 (permalink)
Newbie
 
Join Date: May 2009
Posts: 4
Thanks: 0
Thanked 0 Times in 0 Posts
iTrader Score: 0 reviews
Smile

Quote:
Originally Posted by got...DIESEL? View Post
Don't be so sure. The alternator is just the slave, without the PCM to make it charge it sits cold. Unhook the two small field wires located on the back of the alternator attached with 8mm nuts. Keep them away from grounding on the block etc. Attach two jumper wires, polarity doesn't matter...one to each stud, then the other ends to positive and the other to negative. This will full field the alternator and bypass the regulator. I wouldn't hook up the jumpers until the truck is running. It will display full output so don't leave it that way but for a couple of seconds. Voltage can go sky high by full fielding. Once you have done this, leave the truck running and using a voltmeter check for voltage acrosss the terminals you took off. One wire is pos and the other neg, you should see between 7-12 volts. This will tell you the PCM is supplying field voltage and current to the alternator. In which case keep looking. If the alternator didn't labor the engine, or show high voltage on a meter, it is most likely short on brushes. If it did, well keep looking again.

I wouldn't go throwing an alternator at it until you've diagnosed it down a little further. Taking off the batt cables is not a good thing to do to modern charging systems, and it still doesn't tell you the problem with the charging system.

GL
Chris
Thanks for the informative article.http://www.cumminsforum.com/forum/im...cons/icon7.gif

I tried this with my '95 that won't charge and was getting field voltage from the PCM wires and also got a jump in volts when I briefly full fielded the alternator.

Any other clues or tests would be greatly appreciated.

Thanks, Pile
s-pile is offline   Reply With Quote Quick reply to this message
Old 05-25-2009, 07:10 PM   #11 (permalink)
Super Moderator
 
Join Date: Nov 2005
Location: Montana
Posts: 16,214
Thanks: 27
Thanked 2,120 Times in 1,573 Posts
iTrader Score: 0 reviews
Quote:
Originally Posted by s-pile View Post
Thanks for the informative article.http://www.cumminsforum.com/forum/im...cons/icon7.gif

I tried this with my '95 that won't charge and was getting field voltage from the PCM wires and also got a jump in volts when I briefly full fielded the alternator.

Any other clues or tests would be greatly appreciated.

Thanks, Pile
This indicates your alternator is fine.
Problem is the PCM ($$$) or wiring.
Just install an external voltage regulator.
http://www.cumminsforum.com/forum/94...w-89-02-a.html

External Regulator
__________________
Bill
'95 2500 4wd auto
'95 3500 5 speed heavy hauler
Stock for one day
illflem is offline   Reply With Quote Quick reply to this message
Old 05-28-2009, 07:46 PM   #12 (permalink)
Newbie
 
Join Date: May 2009
Posts: 4
Thanks: 0
Thanked 0 Times in 0 Posts
iTrader Score: 0 reviews
Quote:
Originally Posted by got...DIESEL? View Post
Don't be so sure. The alternator is just the slave, without the PCM to make it charge it sits cold. Unhook the two small field wires located on the back of the alternator attached with 8mm nuts. Keep them away from grounding on the block etc. Attach two jumper wires, polarity doesn't matter...one to each stud, then the other ends to positive and the other to negative. This will full field the alternator and bypass the regulator. I wouldn't hook up the jumpers until the truck is running. It will display full output so don't leave it that way but for a couple of seconds. Voltage can go sky high by full fielding. Once you have done this, leave the truck running and using a voltmeter check for voltage acrosss the terminals you took off. One wire is pos and the other neg, you should see between 7-12 volts. This will tell you the PCM is supplying field voltage and current to the alternator. In which case keep looking. If the alternator didn't labor the engine, or show high voltage on a meter, it is most likely short on brushes. If it did, well keep looking again.

I wouldn't go throwing an alternator at it until you've diagnosed it down a little further. Taking off the batt cables is not a good thing to do to modern charging systems, and it still doesn't tell you the problem with the charging system.

GL
Chris
Thanks for the reply, but just to clarify-

I did get 7-12 volt reading from the regulator wires when truck was running. Doesn't this mean the regulator is working (according to the above field test). Not sure if I understand the test correctly.

p.s. Also got volt jump when full fielding alternator

Thanks again, Pile
s-pile is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Dodge Cummins Diesel Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Display Modes

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Powered by vBadvanced CMPS v3.2.2

All times are GMT -4. The time now is 07:11 AM.



Powered by vBulletin® Copyright ©2000 - 2014, vBulletin Solutions, Inc.

SEO by vBSEO 3.3.2