Alternator not charging.... - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep CJ Forum > Alternator not charging....

FS: 2007-2013 Jeep Wrangler "HALO" Angel Eye KitFS: Wranger BRIGHT License Plate LED! Just $3! Great valueComponent speaker deal for your dash - NalinMFG

Reply
Unread 12-01-2007, 05:26 PM   #1
omanalansanjr
Member
 
omanalansanjr's Avatar
 
Join Date: Dec 2006
Location: McLean, VA
Posts: 145
Alternator not charging....

Alternator Field reading #1 is at 7.5 volts....what does this mean?

Thanks...driving me nutz.....Alternator not charging my battery. And where can i get a new alternator wire harness

Brand new Alternator/battery/cables/starter solenoid

Double/triple tested battery and alternator

__________________
1980 cj7/4 inch lift/32x11.50...in the process
1998 1500 4x4 Dodge ram
2001 r1 yamaha
2003 Audi A4
1966 coupe mustang
oh and pocket bike

Last edited by omanalansanjr; 12-01-2007 at 07:58 PM..
omanalansanjr is offline   Reply With Quote
Unread 12-01-2007, 07:46 PM   #2
bigjoe
Registered User
1977 CJ7 
 
Join Date: May 2006
Location: New Paltz,NY
Posts: 2,035
Why not just replace alt.?
bigjoe is offline   Reply With Quote
Unread 12-01-2007, 07:57 PM   #3
omanalansanjr
Member
 
omanalansanjr's Avatar
 
Join Date: Dec 2006
Location: McLean, VA
Posts: 145
Brand new Alternator/battery/cables/starter solenoid
__________________
1980 cj7/4 inch lift/32x11.50...in the process
1998 1500 4x4 Dodge ram
2001 r1 yamaha
2003 Audi A4
1966 coupe mustang
oh and pocket bike
omanalansanjr is offline   Reply With Quote
Unread 12-02-2007, 08:37 AM   #4
hansh
Registered User
1966 CJ5 
 
Join Date: May 2007
Location: SE WI USA
Posts: 59
Make sure alternator is working, just because it is new does not mean it is good. Remove the wiring and check the voltage coming out of the alternator, or pull it and bring it to a shop and have it bench tested.
__________________
1986 CJ7 Stock, I6
1967 Jeepster Stock, V6
1966 CJ5, V6, D44, locked,.....
1993 Diesel ZJ
www.syntheticwerks.com
hansh is offline   Reply With Quote
Unread 12-02-2007, 09:10 AM   #5
jeepdaddy2000
Web Wheeler
 
jeepdaddy2000's Avatar
1971 CJ5 
 
Join Date: Jan 2002
Location: Eagle Point Oregon
Posts: 6,108
Are we assuming that you have a Motorola system? If so, some systems have a 7V terminal for the auto choke. It may be possible that you have switched the regulator wire to this post. If not and you are comfortable with the wiring to the alternator, you can isolate the voltage regulator and test the alternator separately. It will require connecting an ammeter lead between the battery positive post and the positive brush terminal on the alternator. If you do not have this equipment, have the alternator checked at a FLAPS that provides this service. It may be possible that the voltage regulator, not the alternator that is bad.
jeepdaddy2000 is offline   Reply With Quote
Unread 12-02-2007, 12:24 PM   #6
JeepHammer
Running On Empty...
1973 CJ5 
 
Join Date: Aug 2007
Location: South West Indiana
Posts: 9,952
Assuming a Delco alternator, since my CJ's had Delcos than Motorolas, Prestolites, or Motorcrafts combined...

1980 CJ's came with Delco SI series alternators.
-----------------------

#1, 7.5 volts when the key is 'On',
NO VOLTAGE when the key is 'Off'.

#2 should show battery voltage at all times.

That would be about correct with the resistor in place.
It would be about battery voltage if you were using a Diode instead of the brown factory resistor wire.

The

Here are a couple of things you might want to check first...
1. Fusible link.
The 'Batt' wire on the back of the alternator is connected to the Starter Solenoid, Battery cable side.

That is a 10 Ga. wire, and there is a safety device connected to the starter solenoid called a 'Fusible Link'.
It's about 4" long and will have a ring terminal at one end to connect to the starter solenoid, and a plastic collar connected to the primary charging wire connected to the 'Batt' terminal on the alternator.

If that Fusible Link has burned or corroded into two, then the voltage produced by your alternator isn't reaching your battery.

2. Sense or Sample Wire.
This is the 14 Ga. 'Red' wire in the two wire plug.
It does two jobs, one is 'Sense' or 'Sample' the 'Line' voltage for the alternator regulator,
The other is supply current for the alternator rotor.

This wire on AMC engines usually loops back around to the back of the alternator and connects to the 'Batt' terminal
on the alternator. This is 'OK' for testing, but Delco (the people who manufactured your alternator) and I don't recommend you run your alternator this way everyday.

On some installs, that #2, 'Sense' or 'Sample' wire connects back to the starter solenoid via a 'Fusible Link'.
That Fusible Link should be 16 Ga. and connect to the Starter Solenoid Battery Cable terminal.

You should check both wires for LOAD (not just voltage) at the alternator.

Here are a couple of diagrams that should help chase the wiring...
Here is a wiring diagram WITHOUT an 'Idiot' light,
And WITH a Sense wire 'Jumper', the way most AMC engines are wired...
Take note of the Fusible Link Location!


Here is a diagram with an 'Idiot' light, and with a Sense wire ran back to the starter solenoid...
Take note of both Fusible Links!


NOTICE IN BOTH DIAGRAMS, There is a DEDICATED GROUND WIRE!
Since every electron your vehicle produces or consumes with have to be produced by that alternator,
GIVE IT A DEDICATED 10 Ga. Ground Wire!
--------------

For quick testing, you can make one of these for under $10.



This is the two wire plug from the alternator, but set up with a Diode and a 'Quick Jumper' to the back of the alternator.
(find the diode part number in the diagrams above)

Plug this in, connect the Ring Terminal to the back of the alternator on the 'Batt' terminal,
And touch the open end of the diode to the 'Batt' terminal.
You alternator should begin to charge instantly.
If not, the only other thing that can be wrong is the wire or connector ends from the 'Batt' terminal to the Starter Solenoid, including the 'Fusible Link'.
JeepHammer is offline   Reply With Quote
Unread 12-02-2007, 08:23 PM   #7
kappa505
Registered User
1980 CJ5 
 
Join Date: Oct 2006
Location: Las Cruces, New Mexico
Posts: 459
^^^^^^^should be a sticky.
__________________
"Nothing in the world can take the place of Persistence. Talent will not; nothing is more common than unsuccessful men with talent. Genius will not; unrewarded genius is almost a proverb. Education will not; the world is full of educated derelicts. Persistence and determination alone are omnipotent. The slogan 'Press On' has solved and always will solve the problems of the human race." Supposedly President Coolidge
kappa505 is offline   Reply With Quote
Unread 12-02-2007, 10:13 PM   #8
JeepHammer
Running On Empty...
1973 CJ5 
 
Join Date: Aug 2007
Location: South West Indiana
Posts: 9,952
Quote:
Originally Posted by kappa505
^^^^^^^should be a sticky.
If the moderators so choose (and ask) I'll make a version for permanent posting.
I have write ups on most of the BBS forums, Pirate, Off-Road.com, IFSJA, Jeeps Unlimited, ect.
It won't be a problem to do one for this forum either.
JeepHammer is offline   Reply With Quote
Unread 10-28-2013, 06:32 PM   #9
chaddube
Registered User
1987 YJ Wrangler 
 
Join Date: Oct 2013
Location: black canyon, az
Posts: 16
im having about the same issue except my alt is getting red hot after only seconds of running- everything has been quadrupppple tested so its not alt or battery- read that bypassing the ignition and running a diode directly to the coil might work?
chaddube is offline   Reply With Quote
Unread 10-28-2013, 07:55 PM   #10
LumpyGrits
Registered User
1985 CJ7 
 
Join Date: Jul 2010
Location: The Mojave Desert Palmdale Ca. U.S.A.
Posts: 4,442
Take the belt off and see if the pulley turns smoothly.
You may have a dead bearing.
IF that is not the case. Have the alt tested ASAP, as you risk a electrical fire.
LG
__________________
Have'n you along, is like loose'n 2 good men
LumpyGrits is offline   Reply With Quote
Unread 10-28-2013, 08:42 PM   #11
chaddube
Registered User
1987 YJ Wrangler 
 
Join Date: Oct 2013
Location: black canyon, az
Posts: 16
Quote:
Originally Posted by LumpyGrits
Take the belt off and see if the pulley turns smoothly. You may have a dead bearing. IF that is not the case. Have the alt tested ASAP, as you risk a electrical fire. LG
Pulley good. Alt tested good. Belts good got to be electrical somehow. Alt pushes 14 by itself but when hooked up it drops to 11 and gets hot. Ground maybe??? Got dash apart trying to see if it's in there. Not driving it right now. It's my wheeler. Just missing out on this great wheather
chaddube is offline   Reply With Quote
Unread 10-28-2013, 08:43 PM   #12
chaddube
Registered User
1987 YJ Wrangler 
 
Join Date: Oct 2013
Location: black canyon, az
Posts: 16
Quote:
Originally Posted by LumpyGrits
Take the belt off and see if the pulley turns smoothly. You may have a dead bearing. IF that is not the case. Have the alt tested ASAP, as you risk a electrical fire. LG
Actually pulled the new alt apart today just to check internal parts and it's all good
chaddube is offline   Reply With Quote
Unread 10-28-2013, 10:05 PM   #13
LumpyGrits
Registered User
1985 CJ7 
 
Join Date: Jul 2010
Location: The Mojave Desert Palmdale Ca. U.S.A.
Posts: 4,442
Bad alt. if it drops to 11 vdc.

LG
__________________
Have'n you along, is like loose'n 2 good men
LumpyGrits is offline   Reply With Quote
Unread 10-29-2013, 06:58 AM   #14
chaddube
Registered User
1987 YJ Wrangler 
 
Join Date: Oct 2013
Location: black canyon, az
Posts: 16
Quote:
Originally Posted by LumpyGrits
Bad alt. if it drops to 11 vdc. LG
Have 2. 1 is brand new. Both same result. Both tested good
chaddube is offline   Reply With Quote
Unread 10-29-2013, 07:22 AM   #15
ScroungerLee
Senior Member
1986 CJ7 
 
Join Date: Sep 2013
Location: Ridgefield, CT
Posts: 520
Sounds like a short somewhere that isn't fused. Could the battery be shorted internally?
ScroungerLee is offline   Reply With Quote
Reply
Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.