More electrical gremlins.

[ShadowsPapa]

An exploded Aux? A chewed up Positive cable with a roddent completing the path? I've seen some strange things before. He does and did have a large voltage drop. I still think his fender ground needs to be inspected. Do you remember that guy that inspected his fender ground and found it still attatched to the stud with another ground cable, but the stud was sheared off from the fender? I am trying to find that thread. Maybe around 4 years ago is what I remember.

Absolutely all grounds need to be loosened, and retightened, not just looked at.
Rodents? Well, heck yeah - I had to replace almost all of the wiring under a camper I had because of rodents.
They caused hundreds of dollars of damage to our heatpump outside unit, and - danged squirrel chewed some Christmas lights like they were cut with scissors.
This is a case of leave nothing unchecked.
That was one strange video and yes, the point where it may have been a bump could be a clue as well.

I have the correct cable disconnected. Mine was built prior to the change in 2021 model year.

No question you have the correct cable undone - I can tell by looking (size matters), and you have an early build, and if it was wrong, you'd have nothing. So that's not even something to consider. It's the correct cable.

Sponsored

 

[mtudb24]

If he had the wrong ground disconnected, the whole Jeep is dead. That is why I asked if he had checked the other end at the fender. A loose fender ground is looking more and more probable.

Where is the fender ground I should be looking for? Talked with a GM battery engineer today and he also told me a battery with a dead cell will test fine at rest but will do wacky stuff under load. Tried to get the battery tested today, but work had other plans for me. Taking tomorrow off to try and figure this out.

Thanks everyone for the suggestions. Much appreciated for sure.

 

[mtudb24]

Absolutely all grounds need to be loosened, and retightened, not just looked at.
Rodents? Well, heck yeah - I had to replace almost all of the wiring under a camper I had because of rodents.
They caused hundreds of dollars of damage to our heatpump outside unit, and - danged squirrel chewed some Christmas lights like they were cut with scissors.
This is a case of leave nothing unchecked.
That was one strange video and yes, the point where it may have been a bump could be a clue as well.




No question you have the correct cable undone - I can tell by looking (size matters), and you have an early build, and if it was wrong, you'd have nothing. So that's not even something to consider. It's the correct cable.

Funny you mention rodents. We had a string of Xmas lights in our yard that kept getting "vandalized" and thought it was some kids cutting our lights. Put a trail camera up and found it was a rabbit chewing the string of lights in the wee hours of the night. HAHHAHA

 

[Lost1wing]

The aux has no path to ground with the cable disconnected. It's totally isolated, so even if it had a dead short inside the aux battery, it wouldn't matter to the rest of the system.

The aux battery grounds to the chassis ground, using the top of the IBS as a terminal or junction.
Without that cable connected, the aux battery can't have any impact.

If he pulled the wrong cable, then neither battery has a path to the chassis, so nothing should operate.

I had worked on a dozer where one of the batteries exploded, causing the plate and the post to leave all steal battery box and weld itself to the back wall. The negative fell to chassis ground. The positive just melted away the lead until the cable itself made contact to the enclosure. It was a light show for a few seconds.

 

[kooltoys]

I have the correct cable disconnected. Mine was built prior to the change in 2021 model year. If that were the case, this would have happened long ago back in Oct / November of last year when I bypassed the aux battery (My assumption is). It wouldn't take this long for the problem to arise. And I have changed my main battery about 4 months ago. and again no issues.

Everyone says it cant be but here you are every few months (4) having battery issues for the 3rd time.
I would put it back to stock, charge both batteries separately and see where you are at. Thats what the dealer will tell you.

 

[Lost1wing]

Fender ground is in the area between the fuse box and the main battery, on the inner fender.

 

[ShadowsPapa]

From a tech document -

See the Open Circuit Voltage Table. This voltage reading will indicate the battery state of charge, but will not reveal its cranking capacity. If a battery has an open-circuit voltage reading of 12.4 volts or greater, it may be load tested to reveal its cranking capacity.

OPEN CIRCUIT VOLTAGE TABLE
Open Circuit Voltage Charge Percentage
11.7 volts or less 0%
12.0 volts 25%
12.2 volts 50%
12.4 volts 75%
12.8 volts or more 100%

 

[mtudb24]

All grounds checked. Battery passed the load test but when we put the alternator test tool on the truck, the tester kept saying the voltage regulator failed.

I'm wonder if this is actually a alternator issue? I know the PCM / BCM / IBS control all that voltage stuff.

 

[ShadowsPapa]

Talked with a GM battery engineer today and he also told me a battery with a dead cell will test fine at rest but will do wacky stuff under load.

A battery with a dead cell will test 2 volts low under no load and will crash under a real test.
A 12 volt battery has 6 cells, each putting out about 2.2 volts. If one is dead, you lose the voltage it supplies. A battery can show good voltage at rest, but fail under load. I had that happen with the battery in my SX4 a year or so ago. It read fine voltage-wise, but once any load was on it, it dropped like a rock. Load testing is the only real way to test a battery.

Battery passed the load test but when we put the alternator test tool on the truck, the tester kept saying the voltage regulator failed.

Who is the "we" who did the testing?
Was it a load test of the alternator?
(loading the battery, watching alternator output and voltage)

It could well be the voltage regulation. And if that's the case, the PCM is going to be involved.

 

[mtudb24]

Are there any stored codes at this point?
I wonder about the IBS itself failing.

Either of these?
B2193: Intelligent Battery Sensor Internal
U113E: Lost communication with intelligent battery

Or, as someone else said - serious ground loss issue.

No active or stored codes..

 

[Hootbro]

That minty FLUKE 77 is almost pornographic.

 

[mtudb24]

A battery with a dead cell will test 2 volts low under no load and will crash under a real test.
A 12 volt battery has 6 cells, each putting out about 2.2 volts. If one is dead, you lose the voltage it supplies. A battery can show good voltage at rest, but fail under load. I had that happen with the battery in my SX4 a year or so ago. It read fine voltage-wise, but once any load was on it, it dropped like a rock. Load testing is the only real way to test a battery.



Who is the "we" who did the testing?
Was it a load test of the alternator?
(loading the battery, watching alternator output and voltage)

It could well be the voltage regulation. And if that's the case, the PCM is going to be involved.

I took it up to the shop I usually take my vehicles that are out of warranty. They put the alternator test tool across my battery, had me start the truck, and cycle on headlights, AC, etc while watching the voltage on the tool. The readout on the load tool said regulated voltage controller failed on the display of the tool.

 

[mtudb24]

That minty FLUKE 77 is almost pornographic.

Its my Precious

 

[mtudb24]

A battery with a dead cell will test 2 volts low under no load and will crash under a real test.
A 12 volt battery has 6 cells, each putting out about 2.2 volts. If one is dead, you lose the voltage it supplies. A battery can show good voltage at rest, but fail under load. I had that happen with the battery in my SX4 a year or so ago. It read fine voltage-wise, but once any load was on it, it dropped like a rock. Load testing is the only real way to test a battery.



Who is the "we" who did the testing?
Was it a load test of the alternator?
(loading the battery, watching alternator output and voltage)

It could well be the voltage regulation. And if that's the case, the PCM is going to be involved.

For $60 or so bucks for a IBS sensor, I wonder if its worth the try to replace before heading to dealership? Looking it up on OEM Mopar parts and this is the part number they say

68289207AC

 

[Hootbro]

Its my Precious

I understand.

Sponsored