Aux battery delete now issues

[Andy29847]

If you find a fuse between the auxiliary battery positive and N1, let us know. I've not seen one in the schematics (from FCA) but then, I've not looked at every single line in those, either. It appears to be direct - but, the schematics would show if there's a fuse somewhere.
(OR, a fusible link which was very common in the past)

I’m thinking as I’m writing and it’s not going well. I bet F42 is for the power to operate the relay, not the power being passed through. If that is true, then you are right.

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[ShadowsPapa]

Looks direct to me! Battery positive to N1 and N2

 

[ShadowsPapa]

I’m thinking as I’m writing and it’s not going well. I bet F42 is for the power to operate the relay, not the power being passed through. If that is true, then you are right.

Yes, F42 is for the relay that operates the PCR that separates the two batteries.

The relay that F42 is handlig is on the PCB in the PDC

F42 feeds PCR control relay on the PCB.
When the PCR control relay is energized, it feeds the coil of the PCR and it opens the circuit.
F42 pulled, then when the PCM closes the PCR control relay, it can't feed power to the PCR itself even though the contacts are closed. The PCM sees nothing wrong because it has energized the coil of the PCR control relay, but there's no power going through the control relay on down to the PCR.

(love this stuff)

It's a relay that operates a larger relay. The PCR Control Relay feeds power to the coil of the PCR itself as the PCM can't handle that one directly, but can handle the smaller PCR control relay on the board in the PDC.

 

[Hootbro]

Gee, I'm not the one who is bothered so much by it - but someone else is bugged that I questioned 'why a fuse'...............
That was it, and I was dropping it. I only asked, more of "musing", wondering. That was it. I wasn't ripping anyone and had left it just at that.
But i then I got smacked as if I was picking on the guy. I asked a question.
Just trying to bring tings current, to what we know for a fact, and know NOW. So much for asking a simple question.


Lurkers - suggestions for those wanting to be safe off the beaten path - carry a simple piece of wire with ends that will work on those high current fuse studs. It's simple, easy. For that matter, carry anything that can make a connection between two points. Heavier is better because it makes it more universal for other things.
I carry longer jumper wires "just in case" as I can hot wire alternators or certain other things with a simple jumper.
If your aux goes bad or something else that you can field fix - jumper wires are a friend.
I have jumper wires with clips on the ends. Clip, clip, done. Or a single clip to connect two adjacent studs.

You do not strike me as the "musing" type.

 

[ShadowsPapa]

You do not strike me as the "musing" type.

I do now and then............. is there an emoji for that, or should I just make it clear?
I do "wonder" a lot, ask things out loud at times - what if, or "why this" - without always hating or disliking it, just wondering why is something a certain way. Does it HAVE to be?

Got me in trouble at school for various reasons.

 

[jebiruph]

If you want to pick the fly shit out of the pepper and critique a 7 year old thread with 7 years of hindsight, have at it.

Like I said, I would cut the guy some slack. It was new territory. Not everybody is infallible out the gate like you are.

If it grinds your gears that much, go over there posting and "correct" him.

The guy is still posting here, thanks for the slack.

At the time of that original post, people were still getting used to the dual battery stop start system. A common problem was to park and think the engine was turned off when it was just stopped, then not be able to jumpstart it after the batteries were drained. This frequently resulted in a tow to the dealer for dead batteries . Also at the time, if the aux battery failed the cold start test the JL would never start as the aux battery was tested for every attempted start. So even if you replaced the main battery with a new battery, a dead aux battery meant you were never going to start.

The jumper wire started as an experiment to see what happened when the aux battery was bypassed. I wanted the ability to easily switch back and forth between bypassed and not bypassed and I decided putting a fuse in the wire was the best way to do that. And having a fuse in the wire was not a bad idea anyway.

 

[Hootbro]

The guy is still posting here, thanks for the slack.

At the time of that original post, people were still getting used to the dual battery stop start system. A common problem was to park and think the engine was turned off when it was just stopped, then not be able to jumpstart it after the batteries were drained. This frequently resulted in a tow to the dealer for dead batteries . Also at the time, if the aux battery failed the cold start test the JL would never start as the aux battery was tested for every attempted start. So even if you replaced the main battery with a new battery, a dead aux battery meant you were never going to start.

The jumper wire started as an experiment to see what happened when the aux battery was bypassed. I wanted the ability to easily switch back and forth between bypassed and not bypassed and I decided putting a fuse in the wire was the best way to do that. And having a fuse in the wire was not a bad idea anyway.

Makes sense. I knew it was work in progress early on and you were flushing out some of the "what ifs?" .

 

[ShadowsPapa]

A common problem was to park and think the engine was turned off when it was just stopped, then not be able to jumpstart it

Curious as to what this means.
Like when the ESS stops the engine when you come to a start?
But - when you put it in park, the engine restarts.
So, what was happening? Sorry, can't figure out how the engine was stopped, but not turned off since letting up on the clutch or putting it in park restarts it.
Does that mean they came to a stop and didn't push the big button? Or, they did, but did it again and it was in run mode, engine not running?



Tip for those who find themselves in need of a "jump":
always connect the donor vehicle and run up the idle, or connect a jump pack, and wait a while. It gives you a better shot. Not 100%, but a better shot.
I've watched too many connect then hop in and try the start. That's never been a good way - even back in the 60s. It will often fail.
You at least have a chance....... no guarantees, but a better chance.
Batteries can fail in multiple ways, not always a short - so some may have bigger troubles than others. Some may jump and drive away, some are stuck.

 

[dirtdevil]

Three years ago I deleted the aux and simply ran the aux cables to the main batt terminals. Been working like a champ ever since. I doubt that is the problem. Though I did attach the aux negative to the main rather than tape it off as this person did.

Agree.. I did just that when I added the Genesis dual battery. Have had that for over 2yrs no issues. The main and the small aux battery are in parallel not in series. I however did not pull any fuses or any relays during my install.

 

[Flyboy2109]

Agree.. I did just that when I added the Genesis dual battery. Have had that for over 2yrs no issues. The main and the small aux battery are in parallel not in series. I however did not pull any fuses or any relays during my install.

Yep, the aux system was on a battery…bringing up the aux cables to the main-the aux system then is still on a battery. Pretty simple.

 

[SoK66]

I have 3 ‘21 Sport Max Tows in tour Jeep service. As the “A!” warning lights come on we remove the aux battery ground at the battery, pull the #42 fuse and replace the main battery. No more aux battery issues and the Jeeps work great. Bear in mind these are bare bones Sports. My personal ‘23 Willys has much more technology and when the day comes I’ll probably retain the aux battery and replace both of them.

 

[salvino]

I have never heard of anybody move the Aux battery positive cables to the main battery until now. You may have fried something.

I pulled the aux battery, replaced the main battery with a slightly larger battery and connected the wire from the aux to the main. Did this over a year ago and everything has worked perfectly since then. I did not pull any fuses.

 

[jebiruph]

Curious as to what this means.
Like when the ESS stops the engine when you come to a start?
But - when you put it in park, the engine restarts.
So, what was happening? Sorry, can't figure out how the engine was stopped, but not turned off since letting up on the clutch or putting it in park restarts it.
Does that mean they came to a stop and didn't push the big button? Or, they did, but did it again and it was in run mode, engine not running?

I'm not sure of the exact sequence, but I think the stop button gets pushed before the transmission is shifted to park, which puts the ignition in accessory mode. Then the shifter light flashes to remind the driver to shift to park, which they do and exit the vehicle not realizing they are still in accessory mode and that causes batteries run down.

For some perspective of how rough we had it back then, early on the only colors you could order were white, black, red and granite. There were a few nachos available at some dealers, but you couldn't order that color. Stingray became available around April of 2018. There weren't any third party accessories available at first either, just Mopar accessories.

 

[ShadowsPapa]

I'm not sure of the exact sequence, but I think the stop button gets pushed before the transmission is shifted to park, which puts the ignition in accessory mode. Then the shifter light flashes to remind the driver to shift to park, which they do and exit the vehicle not realizing they are still in accessory mode and that causes batteries run down.

Thanks - I was trying to figure out as I moved mine to the shop - what could I do to cause the situation you describe - and was still scratching my head trying to see just how it could happen.

 

[10ecHarry]

I have never heard of anybody move the Aux battery positive cables to the main battery until now. You may have fried something.

That's the way I did it 5 trouble free years ago.

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