Aux Battery Problems

[darkstar13]

Leave F42 fuse pulled for now. Do you have a volt meter and are all the wires off N-3 now? If no wire on there put meter between N-3 and ground wires on fender and you get no reading you probably have a blown fuse, having N-1 which goes to senisitive electronics unfused very long is not a good idea.
You need to be aware of the simple circuit involved with Aux battery and the PCR , N-3 takes fused main battery power down to the PCR to one side, on the other side of this "switch" is terminated N-1 which feeds the electronics and also the Aux battery positive, so during a s ESS event the PCR opens disconnecting main battery power from electronics but Aux battery is still connected. You could have just pulled the wires off N-1 and N-3 and PUT A JUMPER BETWEEN N-1 AND N-3 if your fuse is good, instead of going back down to the battery with another wire. Don't put the jumper between N-1 and N-2 , I think you are getting it that it's unfused then. I would check carefully to see if you have a blown fuse that is an expensive repair I believe.....Jack

Jack, that is what it was. A blown N3. Again thanks for your help. Ray

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[Jaxmax]

It was a group effort Ray, glad we all could help. Was it expensive to replace fuse?…Jack

 

[darkstar13]

It was a group effort Ray, glad we all could help. Was it expensive to replace fuse?…Jack

I opted out for the mopar ones and picked up 2 for $132. I will keep a spare now. However after replacing both batteries (recharging them both prior to install), [the aux one first with] all terminals still isolated, very carefully installing the new X/N fuse array and all associated terminals, then install the new main battery {terminals isolated} reattached the positive connecter to the main +, then the negative main terminal to the - post and lastly put the f42 fuse in. It cranked over and started immediately and runs fine. The only exception is the dam ESS LIGHT STILL COMES ON. Even if I pull the fuse. I rechecked all connections, voltages were good, N3 OHMs good. I hate to ask any clues or advice. This is open to the whole group that coached me through this once. I just was not sure how to repost this new item. Thanks .Ray

 

[darkstar13]

I think you need to check your fuse array. What is the main battery voltage with the JT running?

I do not know if you have seen the post I left Jaxmax. If you get a chance would you check it out. Thanks. Ray

 

[Lost1wing]

I do not know if you have seen the post I left Jaxmax. If you get a chance would you check it out. Thanks. Ray

I'm glad you figured it out. You also got to play with your Jeep and got to know it a little better too. Some throw in the towel and haul it to the dealer. Great job for sticking with it.

 

[darkstar13]

I'm glad you figured it out. You also got to play with your Jeep and got to know it a little better too. Some throw in the towel and haul it to the dealer. Great job for sticking with it.

Thanks. BUT as I said to Jaxmax after doing all that the ESS LIGHT STILL COMES ON, even if I pull F 42. If I recall correctly just as it was going out of warranty, I took it into the stealership with this problem and he just said there is an inherent problem in this system. Any more suggestions before I shoot it?

 

[Lost1wing]

Ess light? The one on the push button switch?

 

[Lost1wing]

What message is on the ESS page?

F42 only disables the pcr. The batteries remain in parallel. When the ECU performs a test, the ecu will command the pcr to open to sample the two batteries. Pulling f42 prevents the Pcr from opening so the ecu thinks both batteries are at the same voltage.

 

[ShadowsPapa]

Thanks. BUT as I said to Jaxmax after doing all that the ESS LIGHT STILL COMES ON, even if I pull F 42. If I recall correctly just as it was going out of warranty, I took it into the stealership with this problem and he just said there is an inherent problem in this system. Any more suggestions before I shoot it?

Which light? A warning in the cluster - or on the ESS disable button on the center of the dash?
Pulling the fuse won't negate a true ESS error.

I'm curious, without reading every post yet - which of the two ground cables that run to the top of the IBS on the main battery did you disconnect and isolate? They changed that cable in about 22 model year. The truck may still start and operate fine on the aux battery alone if you removed the wrong ground cable of the two at the top of the IBS.

Is the light here? Or a similar shaped error light on the dash/cluster?

 

[darkstar13]

Which light? A warning in the cluster - or on the ESS disable button on the center of the dash?
Pulling the fuse won't negate a true ESS error.

I'm curious, without reading every post yet - which of the two ground cables that run to the top of the IBS on the main battery did you disconnect and isolate? They changed that cable in about 22 model year. The truck may still start and operate fine on the aux battery alone if you removed the wrong ground cable of the two at the top of the IBS.

Is the light here? Or a similar shaped error light on the dash/cluster?

Thank you. The warning symbol in the instrument cluster along with the service system message. The entire connection on both the battery terminal post when reinstalling the new batteries.

 

[darkstar13]

What message is on the ESS page?

F42 only disables the pcr. The batteries remain in parallel. When the ECU performs a test, the ecu will command the pcr to open to sample the two batteries. Pulling f42 prevents the Pcr from opening so the ecu thinks both batteries are at the same voltage.

The one in the instrument cluster,

 

[Lost1wing]

They nick named it the Avengers light.

If you have an AGM charger, connect the leads to the main battery. This will charge both batteries. New or not, they may not have been fuully charged. While the batteries are charging, remove the electrical connector from the IBS and also verify all of your connections are tight. When the batteries finished charging plug the IBS back in.

 

[Jaxmax]

So Ray, everything back to factory , charged up your old batteries, and ESS should be working as normal correct? I am very vague in this but drive it a couple days and see if it clears, might “reset” all by itself. But….I think you are where you were in the very beginning when a knowledgeable member Hootbro told you how to check your batteries , I think your aux battery might be bad if the voltage dropped as you stated , but you already had the blown fuse at that point, so your back at the very beginning. You need to decide if you want ESS or not, and perhaps do the delete if you don’t want it or get an aux battery if you want. I did eliminate totally, including removing the neutral off battery but left the PCR which is just disconnected and got the Z thing to eliminate the light in dash, all the wiring removed is in a plastic bag in aux battery compartment. You got this , check
aux battery again, I think it is bad , please for the love of God be very aware of the ends of wires and don’t blow any fuses, small water bottles slide over the ends is a good idea……Jack

 

[ShadowsPapa]

The entire connection on both the battery terminal post when reinstalling the new batteries.

If you did not take the two cables apart once you took the cables off the main battery then you still had a hot system.
You need to remove the cable assembly from the top of the IBS, take the TWO CABLES APART FROM EACH OTHER, and make sure those ends don't touch ground, disconnect and take off the IBS and set it aside, and then swap batteries. If you just took off the whole thing from the negative post - you left the auxiliary battery connected into the system, never really isolated and disconnected. So you were swapping out a live battery in a hot system (hot electrically since leaving those two black cables connected to each other left the aux battery fully connected to the truck)

 

[darkstar13]

So Ray, everything back to factory , charged up your old batteries, and ESS should be working as normal correct? I am very vague in this but drive it a couple days and see if it clears, might “reset” all by itself. But….I think you are where you were in the very beginning when a knowledgeable member Hootbro told you how to check your batteries , I think your aux battery might be bad if the voltage dropped as you stated , but you already had the blown fuse at that point, so your back at the very beginning. You need to decide if you want ESS or not, and perhaps do the delete if you don’t want it or get an aux battery if you want. I did eliminate totally, including removing the neutral off battery but left the PCR which is just disconnected and got the Z thing to eliminate the light in dash, all the wiring removed is in a plastic bag in aux battery compartment. You got this , check
aux battery again, I think it is bad , please for the love of God be very aware of the ends of wires and don’t blow any fuses, small water bottles slide over the ends is a good idea……Jack

I may have misled you with my verbiage. I DID Replace both batteries. I just charged them before I installed them. Got the bigger 220CCA Odessey AUX and the bigger 850CCA Odessey Main battery. I have rechecked the X/N array and all ohmned good. It seems to run fine. I have put about 30 miles on it so far but that engine cluster light still comes on. I guess I will just keep driving it, monitor the voltages and hope it eventually goes out.

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