Aux switches temporarily unavailable, battery charging- even after aux battery replaced.

[ShadowsPapa]

I went to service appointment this morning. Technician said nothing was wrong- I had to convince service advisor that the message was not normal- and needed to be resolved.
I had to show him the message and explain the impact on switch functionality. He initially thought it was fine that I needed to wait a few seconds until my aux switches would function.

Wow, the guy isn't a Jeep person and definitely not knowledgeable of how these work or electrical systems in general. He didn't even bother to learn or look it up.

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[KentuckyCatFan]

Service advisor has a ton to learn. Very thankful for a seasoned service manager.

 

[Wolf Island Diver]

Mine’s doing it now too, whenever I start up. I regain the switches after a bit of driving. I just removed my Tazer just to eliminate that but I’ll probably be taking it in next week.

 

[KentuckyCatFan]

I got crank battery replaced too and no more issue.

 

[ShadowsPapa]

I got crank battery replaced too and no more issue.

Good move.

 

[Wolf Island Diver]

Update:

My truck died on Thursday. So I went from the Aux switches being unavailable but becoming available after a few minutes of driving to a truck that wouldn’t start, couldn’t lock and unlock the doors, with windshield wipers that wouldn’t stop slowing moving across a dry windshield. Yes, my OFF windshield wipers turned themselves on and wouldn’t stop. Even if I disconnect the battery ground. When I would reconnect, they would start right up, slowly scraping across my windshield. My new Mopar spray jet wipers are ripped all to hell. All the lights were also flashing in random patterns, the dash kept throwing DEF warnings, glow plug warnings, key fob warnings, etc. The truck had gone crazy.

My 1500 Amp jump pack wouldn’t start the truck, I killed it. I called my dealership to let them know I was coming. Jeep roadside assistance, which mine is still active wanted to charge me $120 to tow me to my preferred dealership. Their preferred destination was a Ford dealership! Geico got me to my dealership for no charge.

Because my truck was behind a double gate on the side of my house, the flat bed could not reach it. In a classic catch-22, we had to get the truck started in order to get it to the flatbed to get it to a dealership for not starting ?‍. We killed the tow truck drivers starting pack. So we pulled his Freightliner up to my gate pulled the emergency neutral tab and then pushed my Jeep across the side yard of my house to get it close enough to his truck to use the jumper cables. Good times ?. We had to cha it for 20 minutes before the engine would turn over and then I had to sit in the truck with the RPMs up around 2000 to keep the truck from dying for an additional 10 minutes.

We flatbedded it to my dealership even though the truck would now start. I’m not going to be the guy whose truck dies in one of the busiest bridge-tunnels in the country. They tested and then warrantied both batteries and I got it back Friday. Both were basically shot. I ended up speaking to the technician, my service writer and the service director and came to the following understandings:

• My dealership (a primarily Jeep dealership) says this exact problem is probably the most common thing they see on Gladiators and JLs
• Even the tow truck driver asked, when he pulled up “is it fuel pump or batteries” ?
• All the computer issues, wiper issues, etc are par for the course with this problem. The truck threw 32 low voltage codes. After installing the batteries they do a series of reboots of the ECU to get it straight. They cleared the codes but did not reflash or update it.
• My dealership says they believe that ESS is causing additional issues on the vehicles, especially diesels. For example, the DEF heater stops working and the DEF freezes, and increasing prevalence of starter issues.
• The failure mode they consistently see is the Aux battery dies, and this slowly, quietly kills the main battery. It’s so prevalent they basically don’t see other failure modes even though main battery failures are certainly possible or issues with ESS itself.
• After years of dealing with these issues they don’t think ESS belongs on Jeeps or light trucks at all, especially diesels. Their opinion is that it’s a major liability, can lead to damage of the diesel emission control systems, and will eventually leave you stranded especially if you off road your Jeep.
• The don’t see the computer behavior as a major problem even though it’s dramatic (the wiper issue is pretty common). A couple of reboots pretty consistently gets it straight. Their concern is that there are too many other systems, like the DEF recycler and heater that need power. In other words you do not want your battery to die in these trucks.
• THEY ENDORSED with my stated plan to remove the Aux battery, replace the main with a larger higher quality battery and disable ESS. They said their dealership will not deny warranty for this including the use of a Tazer to disable ESS.
• They said weather changes, e.g. wild temp swings (I had the AC and then heat on in my house on Friday low 40s to upper 70s) tends to kill these batteries
• They also agreed that with this system (especially if you have the diesel) you should use a battery tender if the truck sits more than overnight. That’s probably true even with an Aux battery delete.
  
  
  
  After this incident and now driving the vehicle with two new batteries I’ve come to realize some things:
• My truck runs differently now. This could be purely psychological, but in the last few months it’s begun to sound weird. When I bought it, it sounded like a little school bus or tractor. In the last maybe two months, it sounds off. After the battery replacement it was back to sounding like it’s old self. I’m still skeptical of my own impressions on this one however because the truck never threw any codes, and until recently I didn’t have any warnings.
• My ESS hasn’t worked correctly for over a year. I vaguely remember ESS was pretty consistent when I bought the truck. Starting probably 6 months after I bought it, ESS would rarely engage, usually only after extensive driving. Like it would not work around town, and then suddenly engage when I pulled into my driveway. It was more subtle than this, more like a slow decrease in its working I think the AUX battery has been dying since about 6 months after buying the truck in April 2021. With the new battery ESS engages consistently.
• Unlike the Aux warning, the ESS warning doesn’t appear unless you scroll to that menu. This is an issue, because ESS not being ready can be an early sign that the AUX battery is dying. I know ESS looks for multiple conditions before working but now ESS pretty much works whenever I stop the vehicle. It hasn’t done that since shortly after buying the truck. If you disable ESS of course you won’t ever notice this change and it’s subtle enough that you may not notice decreasing ESS use anyway.
• I’ve got a good dealership. I’ve used these guys for previous Jeeps and always been happy even though I’ve never bought a Jeep from them. I’ve always been able to get a discount elsewhere because of family that works in the business. There was a bit of a snafu picking up my Jeep Friday after hours because of tunnel traffic and after I asked service to leave my keys with the sales guys. They’re going to install my new adjustable track bar and do an alignment for free as a result. I didn’t even complain or ask for that. A customer oriented dealership when you have a modified Jeep is worth it’s weight in gold.
  
  

 

[UDEE]

Very likely a crank or main battery issue. People seem to jump on it being the aux battery when it could as well be the main or crank battery.

Has the main battery been charged and then tested (by a dealer)?
Before you start the truck, don't touch the brake pedal, press the big start button 2 times to put it in run mode without starting. Use the up/down arrows to get vehicle info and then left/right arrows to get voltage, or use the Off Road Pages to display the volt meter. See what the voltage is before you start it.
Then start it and see what the voltage comes up to.

You have the 2020, is that correct?
If so - 3 years is getting long in tooth for these batteries, especially depending on the use - frequency of driving, length of trips and so on.

I found roughly 12.4 volts to be cut-off on stop/start working or not on my 2020 but the aux switches should work clear down to about 11.8 volts if I recall the settings correctly.

Since the AUX apparently gets its juice directly from the MAIN battery, it would make sense to replace the MAIN first. I just tried your instructions and sure enough my MAIN shows 12.4 with key in run position but motor not started. When motor starts, same info menu selection jumps to 14.4, which is obviously current from thank-god-its working electronic alternator. After messing around with all these forums on these ESS etal issues, I've decided to just go and buy a brand new MAIN battery, installed by someone who knows how to install them. Do you think Les Schwab could do that without missing the part about resetting something or other after re-connecting the cables? I'll post here if just replacing MAIN battery resolved my problems - all similar to what everyone else has been posting here and elsewhere. Just wondering where I should go blow $300-$400 market is asking for these high crank batteries.

 

[Mr._Bill]

Since the AUX apparently gets its juice directly from the MAIN battery, it would make sense to replace the MAIN first. I just tried your instructions and sure enough my MAIN shows 12.4 with key in run position but motor not started. When motor starts, same info menu selection jumps to 14.4, which is obviously current from thank-god-its working electronic alternator. After messing around with all these forums on these ESS etal issues, I've decided to just go and buy a brand new MAIN battery, installed by someone who knows how to install them. Do you think Les Schwab could do that without missing the part about resetting something or other after re-connecting the cables? I'll post here if just replacing MAIN battery resolved my problems - all similar to what everyone else has been posting here and elsewhere. Just wondering where I should go blow $300-$400 market is asking for these high crank batteries.

You have two batteries that are paralleled together. Anyone can change the Main Battery, they just need to be careful with the cables while doing it. You can get a new Main Battery delivered to your door for $170 and change it yourself.

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[UDEE]

So there is no resetting of the on board computer or such required? just remove both cable clamps and re-hook all disconnected cables onto new battery? I am supposing the cable from MAIN to AUX must on the positive post of the main...

 

[Mr._Bill]

So there is no resetting of the on board computer or such required? just remove both cable clamps and re-hook all disconnected cables onto new battery? I am supposing the cable from MAIN to AUX must on the positive post of the main...

Computer reset is not required when changing batteries. Both batteries should be changed at the same time, which does results in a reboot since all power is removed. The head unit can take up to 24 hours to fully recover.

When changing batteries, make sure the battery cables do not touch against each other or anything metal in the engine bay. Doing so can blow the high current fuses, resulting in other electrical issues. Other than that, changing the Main Battery is just disconnecting the cables, swapping the battery, and reconnecting it all. Make sure the new batteries are fully charged before installation.

 

[UDEE]

I'm thinking of just changing the main battery then watch and see. Anything wrong with that, other than finding out later that aux also needs changing?

 

[Mr._Bill]

I'm thinking of just changing the main battery then watch and see. Anything wrong with that, other than finding out later that aux also needs changing?

No, that is okay. My Aux Battery was good for another six months after the Main Battery was replaced.

 

[jwilson2899]

I'm thinking of just changing the main battery then watch and see. Anything wrong with that, other than finding out later that aux also needs changing?

Personally I wouldn’t do that. A bad or failing aux battery can kill your new main battery as well, and then you end up right back in this same boat. It’s really best to replace them both at the same time.

 

[ShadowsPapa]

Since the AUX apparently gets its juice directly from the MAIN battery,

No, it's charged through high current fuse N3.
Both are connected in parallel but for charging via the alternator, the aux has it's own fuse from the bus/alternator feed.

Personally I wouldn’t do that. A bad or failing aux battery can kill your new main battery as well, and then you end up right back in this same boat. It’s really best to replace them both at the same time.

And CHARGE both fully before installing.......

I found best results by charging each battery independently when doing a full charge for the purposes of "watching things". If just charging to maintain the battery level when it sits, then connecting to one will catch the other (I charge through the "7 pin trailer connector" and that will "trickle charge" both.
But for a full AGM proper charging, split that negative cable.
That's the only way you will know if there's a problem charging one of them - like it won't accept a charge, or the voltage drops soon after disconnecting the charger and so on.

 

[ShadowsPapa]

Computer reset is not required when changing batteries. Both batteries should be changed at the same time, which does results in a reboot since all power is removed. The head unit can take up to 24 hours to fully recover.

When changing batteries, make sure the battery cables do not touch against each other or anything metal in the engine bay. Doing so can blow the high current fuses, resulting in other electrical issues. Other than that, changing the Main Battery is just disconnecting the cables, swapping the battery, and reconnecting it all. Make sure the new batteries are fully charged before installation.

Computer reset, no but do reset the IBS by disconnecting it from the battery post AND negative cables.
Start fresh with properly charged, fully charged new batteries and reset the IBS.

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