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Murphy's Law... Charging issue. supposed to travel TOMORROW.

LJRockstar

NAXJA Forum User
Well Murphy's law seems to have struck tonight... I'm supposed to be headed out for the weekend from work tomorrow in the XJ. Last order of business for today was to hit the carwash. One of the drive thru ones, not a do it yourself place. I get back in to drive home and load up gear and now the alternator doesn't seem to be working. I got max 12.0dcv on the voltmeter on the drive home. I can only assume that something got wet in the car wash and optimistically it'll dry out by morning and everything will be fine. Realistically, I doubt that will happen.

The XJ is a 1996 with the 4.0 HO engine. It has a brand new Odyssey battery, brand new 2ga battery cables, I'm pretty confident all the engine/body/chassis grounds are good. I've been DD-ing it for about 2 months now with no troubles. typically with no accessories powered up I get an indicated 13.8vdc when driving which is probably more like 14.0~14.2 at the battery terminals with a proper multi-meter if I could actually check while driving. When the A/C blower in running on high that dips to between 12.2~12.6vdc

I did a few tests, tried the ol' tap the alternator to free up the brushes trick. tested all the fuses in the underhood fuse box everything comes up good. got underneath with the multi meter. I have battery voltage at the output cable, but not at pins 1 or 2 in the diagram below. they were both at less than 1vdc.



Can anyone tell me what sort of voltage I should see there?

Has anyone experienced a situation like this before?

Is there maybe a fuse that popped that is not letting voltage get to the field coil?

Any knowledge/help would be greatly appreciated!
 
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year model would help:twak:
 
I get the same issue. Only when driving in rain and puddles. But I have a brand new alt. And bigger feed wires. I found my alternator doesn't like water in it. I can notice the voltage drop when it's acting up. Put her in neutral or park and rev to about 2500 and hold. Usuly takes less than 20 sec for it to dry out and make power. Also, was the field input test done with it running? That's the only time the ecu will command the alt to charge. Is the battery temp sensor ( if you have it, some do some don't. Seems the newer ones do ) there, and reading? Cel?


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I get the same issue. Only when driving in rain and puddles. But I have a brand new alt. And bigger feed wires. I found my alternator doesn't like water in it. I can notice the voltage drop when it's acting up. Put her in neutral or park and rev to about 2500 and hold. Usuly takes less than 20 sec for it to dry out and make power. Also, was the field input test done with it running? That's the only time the ecu will command the alt to charge. Is the battery temp sensor ( if you have it, some do some don't. Seems the newer ones do ) there, and reading? Cel?


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No CEL, yes I did the test with the engine running. I drove it about 15 miles from the carwash to home and it stayed around 11.8~12.0 the whole way. Yes it has a battery temp sensor. I did get the Maintenance Required light on the drive home, but now it's not coming back on.
 
I'd check if the battery temp sensor is getting its power and see if you can do the key trick to get the 2 digit code. They can store the 2 digit code but not call or pend a cel


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I'd check if the battery temp sensor is getting its power and see if you can do the key trick to get the 2 digit code. They can store the 2 digit code but not call or pend a cel


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I scanned it with my code reader while the Maintenance required light was illuminated, code reader said "No codes present." Is there another way to extract codes without the use of an OBDII scanner?
 
Chrysler used a software level on bored reading with a 2 digit counter. 96 should have the digital odometer. Here's a link to the post where I first found out about it. Sometimes there picky and need the parking break up and the seatbelt on for it to work. http://www.xjtalk.com/showthread.php?t=11574


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Thanks! I'm going to go out and give it a shot right now. I'll report my findings in a few minutes.
 
It showed code 24 and 52. I assume both of those have been set by the low voltage. One of the other things I did tonight was get inspected. Everything passed no problem. So I imagine they appeared on the ride home from the car wash

I started it after I was done and heard a whirring sound I've never heard before I can only guess it was coming from the alternator bearings. I'm thinking I'll be taking The crown Vic instead of the xj....
 
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Sorry to hear that. I'll do some lookin and see what the voltage for the field command here in a bit. For now I have to give my buddy a ride ( he's got a broken leg and can't drive) and get pizza for the people here.


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Sorry to hear that. I'll do some lookin and see what the voltage for the field command here in a bit. For now I have to give my buddy a ride ( he's got a broken leg and can't drive) and get pizza for the people here.


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Thanks for your help. At least this happened near home and not 150 miles into my 300 mile trip! And I have a backup car! :spin1:

I've been there with the broken leg. Tell your buddy to do WHATEVER the physical therapist tells him to, no matter how stupid it sounds. They know what they're doing! haha

I'm gonna hit the sheets... Gotta be up at 4:30am tomorrow... :( I'll check the thread in the morning. :cheers:
 
That DG/OR wire comes from your ASD relay and also supplies power to the coil (and other stuff). If the engine runs you should have power on that DG/OR wire, typically battery voltage. No fuses I know of on this wire. The ASD relay should close as soon as it detects a pulse signal (while cranking) from the CPS. Maybe when you tested you didn't have a good enough ground for your volt leads? Possible the splice is bad and you are getting voltage to the coil but not the alternator, seems unlikely.

The dark green wire is the one that regulates the alternator and is typically a few volts lower, as the alternator needs some volts to make more volts. The alternator regulates on the ground side of the field windings.
 
Chrysler used a software level on bored reading with a 2 digit counter. 96 should have the digital odometer. Here's a link to the post where I first found out about it. Sometimes there picky and need the parking break up and the seatbelt on for it to work. http://www.xjtalk.com/showthread.php?t=11574


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96 does not have a digital odo or a battery temp sensor. That didn't start until 97
The 96 obd2 want as "full featured" as the 97+
 
96 does not have a digital odo or a battery temp sensor. That didn't start until 97
The 96 obd2 want as "full featured" as the 97+

I know 96 is a bastard year. Mine was made late in the year. It does not have a digital readout but the speedo/odo is electronically controlled. And it does have a battery temp sensor. I had to move it to my new battery tray when I installed the odyssey battery.

After reading what 8mud said, I'm pretty sure it was just my altnators time to go. Most likely triggered by that fateful car wash. I can't guarantee I had a good ground while testing for the field coil voltage. Engine was good and hot from driving so it was tough to reach up in there. (Excuses excuses...)

The alternator appears to be the original, and looks to have lived a rough life. If I have time this afternoon before I head out for the weekend I'm going to re test the field coil. If that tests good I think it's just time to install a new alt. I've been wanting to anyway but "if it ain't broke, don't fix it" Now it's broke... going to upgrade the output wire to a heavier gauge and a circuit breaker while I'm at it.

Soooo.... recommendations for a good alternator? Whose got what? Locally I have NAPA, AutoZone, and Advanced Auto for parts stores. I'm not afraid to mail order, but I'm not sure I'm willing to spend dealer money for factory parts. Anyone have a source for rebuilding parts that are good? (Read "not Chinese?")
 
If you are in a hurry Autozone. But there is a reason you need the lifetime warranty with it.
If you have the time and not in to much of a hurry. Grand Cherokee 136a swap
 
If you are in a hurry Autozone. But there is a reason you need the lifetime warranty with it.
If you have the time and not in to much of a hurry. Grand Cherokee 136a swap

^^^^ This. I put in a yellow top (ducks), 136a alternator and 4 gauge wires with an inline fuse. Went from barely reading 9 on the gauge to a solid 14 with A/C, later model XJ fan and my high speed 2 speaker radio system. I upgraded the headlight harness also which seems to have helped before I installed the alternator.
 
Thanks guys. I like the Grand Cherokee swap idea. I'll have to look into how much work that is. I work in a machine shop so modding the bracket isn't a big deal, I'd just rather not do it. haha.

I found this place: Alternator Starter Rebuild Kits assuming my rotor isn't smoked these guys seem to have a nice kit put together, and they offer a high amp stator winding. It's just over $100 including shipping to come up with a 150A alternator thats in my original case so I know it'll fall into place no problem. Anyone used them before?
 
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