Stop Vehicle Now - Updates Alternator ?

[WILDHOBO]

Yes Mopar Part. I can share when we get home old one is on table.

Thanks. I’m going to order one to have in the glove box. Thanks for sharing your frustrating time so we can learn.

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[Mojave20]

Thanks. I’m going to order one to have in the glove box. Thanks for sharing your frustrating time so we can learn.

68368853AA if you have standard alternator.
IIRC it’s 68368854AA with the tow package with larger alt.

https://www.northridge4x4.com/fits/...sories/68368853aa-mopar-oem-z-case-fuse-array

I purchased mine through Northridge.

 

[sarguy1941]

Yup thats the one I got.

68368854AA

I didn't have time to order online as vehicle was needed so got hosed at stealership, but I did order a spare to put in the shop. Probably never need it again but if its on the shelf I wont.

 

[sarguy1941]

So last night went to dinner and a few places. Was dark ran headlights and heat along with radio and what not. Its an hour ride each way plus some travel around town. Voltage stayed around 14.4 when running but dropped to 12.6-8 on auto start.

Today went to run to lowes again and voltage on startup was 13.5. Didn't really pay attention until we were leaving dinner and noticed it at 12.7. Stopped for fuel and restarted and it poped up to 13.8 for 10 seconds then back to 12.7. On way home it dropped to 12.6. Pulling in driveway was at 12.5.

Grabbed meter and it measured 12.6 with it running. Took off ground to AUX battery and no voltage change. Removed ground from main battery and truck quit. Put grounds all back together to start back up. On start up voltage went to 14.4 and dash said auto start not ready. With the auto start in yellow. Voltage showed 14.4. I'm guessing thats from pulling the ground quick and IBS got confused ?

Anyway checked all wires on alternator and they look good. Multiple starts show the auto start not working. Decided to leave it for the night. Put charger on main battery. Showed 13.2 before closing hood. My gut tells me alternator is bad or intermittant ? Every vehicle I have owned you can remove ground and vehicle will run. Ive swapped batteries in Jeeps in the past while running.

Maybe @ShadowsPapa has a thought ?

 

[ShadowsPapa]

So last night went to dinner and a few places. Was dark ran headlights and heat along with radio and what not. Its an hour ride each way plus some travel around town. Voltage stayed around 14.4 when running but dropped to 12.6-8 on auto start.

Today went to run to lowes again and voltage on startup was 13.5. Didn't really pay attention until we were leaving dinner and noticed it at 12.7. Stopped for fuel and restarted and it poped up to 13.8 for 10 seconds then back to 12.7. On way home it dropped to 12.6. Pulling in driveway was at 12.5.

Grabbed meter and it measured 12.6 with it running. Took off ground to AUX battery and no voltage change. Removed ground from main battery and truck quit. Put grounds all back together to start back up. On start up voltage went to 14.4 and dash said auto start not ready. With the auto start in yellow. Voltage showed 14.4. I'm guessing thats from pulling the ground quick and IBS got confused ?

Anyway checked all wires on alternator and they look good. Multiple starts show the auto start not working. Decided to leave it for the night. Put charger on main battery. Showed 13.2 before closing hood. My gut tells me alternator is bad or intermittant ? Every vehicle I have owned you can remove ground and vehicle will run. Ive swapped batteries in Jeeps in the past while running.

Maybe @ShadowsPapa has a thought ?

You can literally fry electronics and alternators taking the batteries out of the circuit with engine running. They need it as a sort of load/buffer.
More later.... Not at home now.......getting noisy here...

 

[sarguy1941]

Interesting Ive swapped batteries for years on the jeep trails. I know its not the best thing to do but when you have dead batteries its the only option.

I guess I'll wait for more info. I need the vehicle fixed before I leave town again. I did find the document you posted in the past about low voltage but I just don't get why the voltage would drop continuously with headlights and heat running if it is charging. I know normally no one sees those screens and maybe I need to just trust the truck and change back to MPG screen and not watch volts.

I also assume I need to reset IBS tomorrow to clear up the "autostart" light. I'll leave it on charge tonight regardless.

 

[ShadowsPapa]

So last night went to dinner and a few places. Was dark ran headlights and heat along with radio and what not. Its an hour ride each way plus some travel around town. Voltage stayed around 14.4 when running but dropped to 12.6-8 on auto start.

Today went to run to lowes again and voltage on startup was 13.5. Didn't really pay attention until we were leaving dinner and noticed it at 12.7. Stopped for fuel and restarted and it poped up to 13.8 for 10 seconds then back to 12.7. On way home it dropped to 12.6. Pulling in driveway was at 12.5.

Grabbed meter and it measured 12.6 with it running. Took off ground to AUX battery and no voltage change. Removed ground from main battery and truck quit. Put grounds all back together to start back up. On start up voltage went to 14.4 and dash said auto start not ready. With the auto start in yellow. Voltage showed 14.4. I'm guessing thats from pulling the ground quick and IBS got confused ?

Anyway checked all wires on alternator and they look good. Multiple starts show the auto start not working. Decided to leave it for the night. Put charger on main battery. Showed 13.2 before closing hood. My gut tells me alternator is bad or intermittant ? Every vehicle I have owned you can remove ground and vehicle will run. Ive swapped batteries in Jeeps in the past while running.

Maybe @ShadowsPapa has a thought ?

Looking again at the voltages you saw prior to doing anything - I don't really see an issue.
it's normal for these, if the battery is fully charged and the temperature is high (I don't know what the temperature there is or was or the battery temp at the time) for these to drop back to 12.6-12.8
It can vary the voltage from say 12.7 when going up a hill and then pop up over 13 when coasting down a hill.
These only produce what is needed to keep things operating, and keep the battery full, and will pull back if the battery is full, the IBS indicated full charge and sensed a warm battery.

One thing to do is to charge both batteries independently, and reset the IBS and try it all again, but for pulling cables loose on a running vehicle? That's been bad since the days of the first alternators and got worse with time.
Pulling cables from an alternator or disconnecting batteries on a running system is a huge no-no. It can literally blow your electronics, pop alternator diodes and more.
Just don't.
If you have done it and it worked - you got really lucky.

This is in all of the tech books I have on charging systems, TSMs, GM and Motorola and other tech documents on charging systems ->

 

[jebiruph]

OK> So update. Replaced both main and aux battery. Aux Battery showed 10.60 when removed. Main is 12.6.
Vehicle Off
New Battery Main - 13.12
Aux - 12.35

Both batteries have chargbed multiple times over night before I got home. Charger shows full on both.

I removed N1 and M3 and measured DC voltage on both cables and it matches the 12.35-49

Start vehicle and dash throws alarms and shows battery voltage 11.5

Battery Voltage with vehicle running 14.56

PCM Via JSCAN shows 11.37

I did continuity test on ZBar Fuse - N1 and N3 appear to be tied together. N2 and all other posts appear together. Voltage on all posts with vehicle off or on.

I'm at a loss. Checked F42 and fuse is good. How can it not show 12+ volts on PCM but show 14+ on battery when running.

Most likely it was a blown N3 fuse and the N4 fuse can usually be used as a substitute by moving the N3 cable to the N4 terminal. https://www.jeepgladiatorforum.com/forum/threads/ess-dual-battery-system-operation.44028/post-709139

 

[sarguy1941]

Looking again at the voltages you saw prior to doing anything - I don't really see an issue.

OK. I'll pull the grounds this morning to get the IBS to reset again. Hopefully that clears the autostart not ready alarm also. It was just odd that the voltage never went up and actually went down when I turned on the heat and lights. To me that should have triggered something. Being I work out of town all week really don't want to have wife need to call for a tow again this week. We have crap cell around us and last week was pretty crazy trying to get help. It was in the mid 50's yesterday and think its the same today.

Wish there was a way to test the alternator in the vehicle. I've taken known working ones to the parts store in the past and gotten told "its bad" so I don't trust them anymore. Especially on a $800 one.

 

[sarguy1941]

Most likely it was a blown N3 fuse and the N4 fuse can usually be used as a substitute by moving the N3 cable to the N4 terminal. https://www.jeepgladiatorforum.com/forum/threads/ess-dual-battery-system-operation.44028/post-709139

Correct along with bad batteries the N3 fuse was blown. I did move it to N4 to test but wasn't sure the amperage until I got the new one. The old one had no numbers on it. The new one lists both posts at 150amps so at least I know for future.

 

[WILDHOBO]

OK. I'll pull the grounds this morning to get the IBS to reset again. Hopefully that clears the autostart not ready alarm also. It was just odd that the voltage never went up and actually went down when I turned on the heat and lights. To me that should have triggered something. Being I work out of town all week really don't want to have wife need to call for a tow again this week. We have crap cell around us and last week was pretty crazy trying to get help. It was in the mid 50's yesterday and think its the same today.

Wish there was a way to test the alternator in the vehicle. I've taken known working ones to the parts store in the past and gotten told "its bad" so I don't trust them anymore. Especially on a $800 one.

With a good scanner, you can sometimes to an alternator test. Mine can.

 

[sarguy1941]

So, I was just out playing with Jscan looking for IBS %….
anyways, my jeeps batteries are a couple months old and regularly show 12.2-12.4v resting voltage….
Jscan shows the battery life at almost 87%.

I am saying the table below is gospel… but it seems to be pretty close

OP- Jscan is fairly simple to navigate for the basics of reading codes and what not. This won’t help you at all now. But might be worth downloading the app- same for your wife and keeping this in the center console:
https://a.co/d/fCBMkU4

Where did you find this screen in JSCAN ? I looked for it under them odules but only ever found battery voltage.

 

[sarguy1941]

With a good scanner, you can sometimes to an alternator test. Mine can.

I was hoping JSCAN would show this but have not found it yet. I have another plug in scanner in my work truck so may try that one. I dont recall that one being able to see much.

 

[WILDHOBO]

I was hoping JSCAN would show this but have not found it yet. I have another plug in scanner in my work truck so may try that one. I dont recall that one being able to see much.

Mine can do active tests, and I’m pretty sure alternator test is among them. I racking my brain for what scanner it is…it’s an Innova 5xxx I’m pretty sure. Got it at AutoZone.

Edit 5160rs.

 

[Escape.idiocracy]

Where did you find this screen in JSCAN ? I looked for it under them odules but only ever found battery voltage.

You need to go into the modules section, scroll down to powertrain control, then the yellow dot and select what you would like to view. There is seriously a ton of things to weed through in each module… ? so I think it helps if people post screen shots of what they are reviewing…. Some of these settings/views are algorithms and some are live feeds of sensors- so keep that in mind.

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