Alternator Regulator Issues ....
#1
Senior Member
Thread Starter
Join Date: Feb 2011
Location: Bel Air, Maryland 21015
Posts: 719
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1995
Model: Cherokee
Engine: 4.0
Alternator Regulator Issues ....
So I had trouble and took the 98 ZJ ( 4.0 I6 ) to a service center.
Their tester indicates a GOOD BATTERY but " Low Voltage From Alternator ".
I told the guy " the alternator is externally regulated, can you test the regulator? "
He was a new kid and wasn't sure, but he did know how to use the machine.
Symptoms do indicate charging system trouble --- run the jeep all day and OK, but run it for extended time with HEADLIGHTS ON ( high load ) and the battery runs down.
Before I install a new ALTERNATOR is there any way to test the VOLTAGE REGULATOR ????
I know the regulator is on the PCM.
THANKS !!!!!!
Their tester indicates a GOOD BATTERY but " Low Voltage From Alternator ".
I told the guy " the alternator is externally regulated, can you test the regulator? "
He was a new kid and wasn't sure, but he did know how to use the machine.
Symptoms do indicate charging system trouble --- run the jeep all day and OK, but run it for extended time with HEADLIGHTS ON ( high load ) and the battery runs down.
Before I install a new ALTERNATOR is there any way to test the VOLTAGE REGULATOR ????
I know the regulator is on the PCM.
THANKS !!!!!!
Last edited by KD3NE; 11-08-2012 at 05:25 AM.
#2
CF Veteran
Join Date: Mar 2010
Location: Broward County Fl.
Posts: 47,923
Likes: 0
Received 22 Likes
on
22 Posts
Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
Why replace battery if alternators not operating properly just replace alternator never really heard of any regulators going bad in Pcms .. just saying
#3
Senior Member
Thread Starter
Join Date: Feb 2011
Location: Bel Air, Maryland 21015
Posts: 719
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1995
Model: Cherokee
Engine: 4.0
I know it is rare but a search indicate a few have had to swap out the PCM due to failed regulator.
#4
Senior Member
Thread Starter
Join Date: Feb 2011
Location: Bel Air, Maryland 21015
Posts: 719
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1995
Model: Cherokee
Engine: 4.0
I bought a new ALTERNATOR ...
It is a 120 Amp Bosch Reman
They asked if I wanted 90 Amp or 120 Amp .
I figure bigger is better!
Just hope it fits in fine!
It is a 120 Amp Bosch Reman
They asked if I wanted 90 Amp or 120 Amp .
I figure bigger is better!
Just hope it fits in fine!
Last edited by KD3NE; 11-08-2012 at 12:31 PM.
#5
Old fart with a wrench
Be aware there is a temp sensor underneath the battery that tells the PCM to cut back alternator output if the battery gets too hot. They have been known to go bad.
#6
CF Veteran
Join Date: May 2010
Location: New Hampshire
Posts: 1,013
Likes: 0
Received 1 Like
on
1 Post
Year: 1997
Model: Grand Cherokee
Engine: 4.0
Hey Dave, what do you mean there is a temp sensor under the battery location? What year range ZJ does this cover and what does it look like? Is it the button looking thing or a mat design?
Last edited by 1ABrian; 11-08-2012 at 10:08 AM.
#7
Old fart with a wrench
My 97 ZJ had one. The alternator was overcharging the battery and was boiling the acid away. I was alerted to this by someone on CJ. Changed it, cured problem. Yes. its a button looking thing under the center of the battery. Mine was white with corrosion.
Last edited by dave1123; 11-08-2012 at 10:10 AM.
Trending Topics
#9
Senior Member
Thread Starter
Join Date: Feb 2011
Location: Bel Air, Maryland 21015
Posts: 719
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1995
Model: Cherokee
Engine: 4.0
My guess is that it is a THERMAL SWITCH.
Do you know if it is " Normally Open " or " Normally Closed "?
Knowing that would make testing, possible.
I am going to guess it is " Normally Closed ".
Thanks
#11
CF Veteran
Join Date: May 2010
Location: Western Michigan
Posts: 1,680
Likes: 0
Received 4 Likes
on
4 Posts
Year: 1993
Model: Grand Cherokee
Engine: 4.0l inline 6
I didn't know about the temp sensor. The guy at advance auto ran a test and my alt is about gone. Did the bosch higher volt alt work well? any issues?
Thread
Thread Starter
Forum
Replies
Last Post
carverdave
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
7
02-06-2019 08:55 AM
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)