Aux Battery Cables

[THAW]

Mostly. The cooling fans and electric power steering are on other N terminals, as they are very high amperage. (So is the alternator output)
So the best way to think about it is N1 and N2 have to have power 100% of the time for everything electric to function.

Not really. While it's true the RAD FAN is on N5 and the EHPS is on N6, N2 doesn't need power from the CR[an]K battery when the Jeep is running (plus the Jeep can run without power to N5 and/or N6). And, N3 could provide power to N5/N6 via the AUX (ESS) battery even with the Jeep ignition off. But that's all esoteric...

Like I said, the best way to think about N1 is: it's the Jeep. A power source is always required there for the Jeep to operate.

Sponsored

 

[AzCoronaDog]

Not really. While it's true the RAD FAN is on N5 and the EHPS is on N6, N2 doesn't need power from the CR[an]K battery when the Jeep is running (plus the Jeep can run without power to N5 and/or N6). And, N3 could provide power to N5/N6 via the AUX (ESS) battery even when the Jeep ignition off. But that's all esoteric...

Like I said, the best way to think about N1 is: it's the Jeep. A power source is always required there for the Jeep to operate.

The alternator alone is not meant to run everything on these vehicles, and without a battery to buffer everything, the computers will not be happy. The aux battery alone will not work for long either, especially if it has to power N5 and N6, it simply cannot supply the amperage.
Running without a fan or power steering can be done, but without the fan here in AZ, you won't be running for long!
But yes, I do agree that N1 is the major player for everything that will allow the motor to run.
For me, when I remove the aux battery, I prefer the jumper method and getting rid of the extra cables. Since you have to get to the horrible aux battery location anyway, I figure I'd rather just remove them while I'm there than tape them up, and have ALL the main power running through those cables.

 

[Mguy]

There are certainly several ways to successfully eliminate the aux battery, but when my warranty is up and I do that fix, I will use a jumper from N1 to N3, so the original factory setup of N1 having a 150a fuse back to the main battery remains.

Not to criticize your work, but apparently you are not aware that JL models without the aux battery (but still with ESS) come stock utilizing a strap (jumper) connecting N1 to N2. The 150 amp fuse at N3 is not needed to protect the N1 connection, or downstream loads, at all.

 

[AzCoronaDog]

Not to criticize your work, but apparently you are not aware that JL models without the aux battery (but still with ESS) come stock utilizing a strap (jumper) connecting N1 to N2. The 150 amp fuse at N3 is not needed to protect the N1 connection, or downstream loads, at all.

I have not looked at the other Jeep setups, so I was not aware they used a jumper from N1 to N2 rather than N3. (And I have no issue having my ideas criticized, I have been wrong before, and will be wrong again! LOL)
I just figured it was there for a reason on my Jeep, so why not connect there. Maybe because the power control relay can only handle 150a? Either way, it shouldn't matter, as I said in another post, if N1 draws more than 150a, you have bigger problems!

 

[THAW]

I will use the jumper, remove all the aux battery cables, box, etc., and keep F42 in place so ESS can still work if I hit my head and think it is a good idea for some reason.

The presence/state of fuse F42 is irrelevant once the AUX (ESS) battery cabling is removed, since the PDC will be disconnected.

 

[AzCoronaDog]

The presence/state of fuse F42 is irrelevant once the AUX (ESS) battery cabling is removed, since the PDC will be disconnected.

I have to test again, but will the ESS system function without it? I think my '24 came up with an ESS not ready message when that fuse was out.
Kind of a mute point, as I really don't think I will ever want to use ESS anyway, I just don't like error messages on the display if I can avoid them.

 

[AzCoronaDog]

I wanted to see if pulling F42 gives an error message or not, but apparently my Jeep detected I have been talking about the evil ESS, and has decided it will not let me test the system.
1. I started it, hit the ESS switch to turn it back on (my module turned it off) -
get ESS not available, door is open message.
2. Closed the door - get ESS not available, seatbelt not fastened message.
3. Fastened my seatbelt - get ESS not available, engine is not up to temperature message.
4. Let the Jeep run (it is 105 out right now) until temp at mid range - get ESS not available, outside temperature too high message. (Why was this not the very first message?)
5. I give up. I will try again in the morning when the temp is slightly less than the surface of the sun.

 

[THAW]

I have to test again, but will the ESS system function without it? I think my '24 came up with an ESS not ready message when that fuse was out.
Kind of a mute point, as I really don't think I will ever want to use ESS anyway, I just don't like error messages on the display if I can avoid them.

I wanted to see if pulling F42 gives an error message or not, but apparently my Jeep detected I have been talking about the evil ESS, and has decided it will not let me test the system.
1. I started it, hit the ESS switch to turn it back on (my module turned it off) -
get ESS not available, door is open message.
2. Closed the door - get ESS not available, seatbelt not fastened message.
3. Fastened my seatbelt - get ESS not available, engine is not up to temperature message.
4. Let the Jeep run (it is 105 out right now) until temp at mid range - get ESS not available, outside temperature too high message. (Why was this not the very first message?)
5. I give up. I will try again in the morning when the temp is slightly less than the surface of the sun.

ESS works without fuse F42 - though it may be limited to 6 events per ignition cycle.

Pulling fuse F42 doesn't cause a dash warning light, it prevents a circle-A! dash warning light when the AUX (ESS) battery is removed.

 

[AzCoronaDog]

ESS works without fuse F42 - though it may be limited to 6 events per ignition cycle.

Pulling fuse F42 doesn't cause a dash warning light, it prevents a circle-A! dash warning light when the AUX (ESS) battery is removed.

Thanks - I will verify when my Jeep cooperates!

 

[mbrose1994]

The best way to think about N1 is: it's the Jeep (fuse box). That is, N1 is where the battery/batteries and/or alternator/PPU are sending power.

N1, N2, N3 - complex Jeep design

• AuxBatt (factory) POS to N1, N3.
  • N1 powers Jeep stuff separate from N2 thru N6
  • N3 is only for charging AuxBatt
  • N3 does not power Jeep
• PrimBatt (factory) POS to N2
  • powers Jeep except for N1 powered stuff

Single battery modification:

• Remove AuxBatt POS to N1, N3
• Move PrimBatt POS to N1
• Jump N1 to N2

How is PrimBatt POS on N2 and jump N1 to N3 better
than PrimBatt on N1 and jump N1 to N2?

 

[THAW]

N1, N2, N3 - complex Jeep design

• AuxBatt (factory) POS to N1, N3.
  • N1 powers Jeep stuff separate from N2 thru N6
  • N3 is only for charging AuxBatt
  • N3 does not power Jeep
• PrimBatt (factory) POS to N2
  • powers Jeep except for N1 powered stuff

Most of your N# descriptions are wrong/incomplete.

• N1 is the electrical path to the PDC (fuse box), it is powered by the AUX (ESS) battery AND/OR the alternator and CR[an]K battery via N3 and the AUX (ESS) battery positive cable
• N3 connects to the AUX (ESS) battery, but isn't "only for charging the AuxBatt", it's also the electrical path from the alternator and CR[an]K battery to Jeep electronics via the AUX (ESS) battery positive cable that connects N3 to N1
• N2 is connected to the CR[an]K battery and therefore allows the CR[an]K battery to provide power to N3 (and indirectly N1), N5, and N6

You don't need to add a jumper when removing the AUX (ESS) battery if you leave the AUX (ESS) battery positive cable in place, it already connects N1 and N3. You just need to remove fuse F42 so the PCR doesn't open, or move the AUX (ESS) battery positive cable terminal connector to the CR[an]K battery positive post to bypass the PCR.

 

[mbrose1994]

Most of your N# descriptions are wrong/incomplete.
I am in learning mode, so accepted. And trying to understand below.

• N1 is the electrical path to the PDC (fuse box), it is powered by the AUX (ESS) battery AND/OR the alternator and CR[an]K battery via N3 and the AUX (ESS) battery positive cable

?? CRK batt POS is connected N2. And simultaneously to N3, and via N3 to N1?

• N3 connects to the AUX (ESS) battery, but isn't "only for charging the AuxBatt", it's also the electrical path from the alternator and CR[an]K battery to Jeep electronics via the AUX (ESS) battery positive cable that connects N3 to N1

?? N3 connected to CRK batt too? Via the Aux batt POS?

 

[Mguy]

Perhaps a few readers are benefiting from this thread. Perhaps, along with a poster or two, readers could benefit from being reminded that the aux battery is not needed for the Jeep's operation. The aux battery and it's convoluted and flawed circuitry was added, and the the N1 to N2 direct connection was removed, when some mad Jeep engineers conspired to keep Jeep owners occupied on the internet rather than running their Jeeps with a reliable electrical system. They were aided by the foolish belief that ESS should be made available to those who stubbornly believe they should have it.

 

[THAW]

I am in learning mode, so accepted. And trying to understand below.

?? CRK batt POS is connected N2. And simultaneously to N3, and via N3 to N1?

?? N3 connected to CRK batt too? Via the Aux batt POS?

Understood, I wasn't criticizing I was trying to help you learn (and correct some confusion)

The high current Z-Case fuse array connects N2 through N8. The fuse array is then connected to N1 via N3 (though the PCR can break this connection). Therefore, all the power sources are capable of powering the Jeep electronics at N1 via their connection to the fuse array and the fuse array's connection to N1. That's the way electricity works.

To disconnect the AUX (ESS) battery, all that's required is removing it's ground and fuse F42. You don't need to remove any positive connections; if the AUX (ESS) battery isn't grounded no current can flow in/out of it.

If you want to physically remove the AUX (ESS) battery, disconnect it's terminals, insulate/secure the terminal connectors/cables and pull fuse F42. An alternative to removing F42 is attaching the AUX (ESS) battery positive cable terminal connector to the CR[an]K battery positive post.

Jumpers are only required when choosing to remove all the factory AUX (ESS) battery cables - which can be done, but is unnecessary.

 

[Mguy]

To disconnect the AUX (ESS) battery, all that's required is removing it's ground and fuse F42. You don't need to remove any positive connections; if the AUX (ESS) battery isn't grounded no current can flow in/out of it.

Not so, bold clause above confuses. The aux battery is electrically isolated simply by disconnecting it's negative. F42 is on the positive side of the circuit. Removal of F42 assures that the aux battery positive stock wiring continues to power N1 (and keep nuisance imaging off the dash) by keeping the PCR always closed.

Sponsored