Jumperless aux battery/PCR bypass

[GingerBeard995]

In terms of impact on anything. Realistically there shouldn't be any if done correctly and so long as regular preventative maintenance is done otherwise. Generally speaking, repairs and maintenance weren't exactly things that occurred often in my household growing up. And if it was, it was never something I was pulled aside to learn. More often than not things were just replaced when they were broken beyond repair.

Which is fine I suppose so long as somebody can afford it and is willing to pay for it or it's covered under a warranty. Many times that wasn't the case though. So solutions such as these are invaluable to people such as myself who want to learn how to care and maintain things to AVOID dealing with broken things in the future.

Thank you ShadowsPapa. And a big thanks to jebiruph and all the other forum members that share their invaluable knowledge with people such as myself who are eager to learn and become more self sufficient. My inquiry comes from a place of curiosity and not of skepticism. I think if this solution has been a widely accepted solution to the issues with the AUX battery, more people should give thanks and credit to where credit is due. Even just an update to say that everything still works exactly as it should after X amount of miles or years.

Which that being said, is a fair point about my wife's Wrangler battery. I should source a decent replacement for that sooner rather than later.

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[Lunentucker]

Hi everyone. I just wanted to potentially get some feedback from owners that have done this Jumperless AUX battery / PCR bypass.

Some time has gone by now and this means of bypassing the AUX battery has grown quite a bit in popularity. So much so that it is one of the most common pieces of advice that many Wrangler JL and Gladiator JT owners give to new Jeep owners to avoid any unnecessary headaches down the road. I've read through all 9 pages of this thread. The general consensus appears to be that if the bypass is done correctly then there shouldn't be any warning lights, "avengers" lights / ESS warnings. And if there is, it also doesn't necessarily mean there are any issues with the bypass but rather a number of other possibilities.

So I guess simply put. To those of you who have bypassed the AUX battery with decent or even newer main batteries, has everything been operating normal? I would think yes but if so, how long has everyone been driving their Gladiators since doing the bypass?

Reason for asking is that I just recently purchased a 2021 Gladiator and did the jumperless bypass myself. No issues as of yet. Though I've only driven it a handful of times around the block since then. And that's only because of some issues with transferring registration when purchased the truck from another state. That's a long story though and probably more suited for it's own thread. BUT the truck will be on the road soon for regular day to day use here in the Northeastern U.S.

My wife has a 2019 Wrangler that we've owned for a little over 3 years now. It has the 2.0 engine and the battery is still going strong (unsure if it's the original). If others have been using the bypass for awhile without issue and my truck goes without issue as well, I'll definitely be doing the bypass to my wife's Wrangler. Probably sooner rather than later.

But would love to hear some feedback from owners after doing the bypass themselves!

Thanks everyone!

I did the DIY bypass and ran it for two years with absolutely zero issues.
If I were to get new one, it would be one of the first things I did.
The "keeps the electronics stable during ESS events" thing is horse pucky, as far as I am concerned. An unreliable and potentially unstable battery keeping things stable makes no sense.
Other makers do ESS without an auxiliary battery of any sort.

At the end of the day, make your own choices. I just chose to not live with the unknown of having one battery cannibalize the other and giving me a nasty surprise.
Bypassing the AUX cuts your failure chances in half, if not more.

 

[Mr._Bill]

If you do the Aux bypass, there is no question as to which battery needs replaced when it dies on you.

 

[Frida2020]

I was looking at the fuse descriptions on the underside of the PDC cover and saw this - F42 PCR CTRL FEED (ESS)*. Removing this fuse defeats the cold start aux battery test and allows the aux battery to be disconnected without generating any errors.

Unplugging the PCR has always been an alternative to using an N1 N2 fused jumper, both methods defeat the aux battery pass/fail test that occurs prior to a cold start. Unlike using a jumper, unplugging the PCR doesn't require any additional parts, it's just not easy to get to the PCR plug. Removing the F42 fuse accomplishes the same thing as unplugging the PCR, both actions prevent the PCR from activating and separating the batteries.

Here's the underside of the PDC cover showing the description and location of the fuse.

Here's the fuse location with the fuse removed.

Here's the schematic showing the fuse in the circuit.

This was extremely and helpful! Thanks so much for sharing.

 

[remlemasi]

Do we think this is an acceptable mod for a post-2021 JL/JT? No washers, second cable is for the winch, nut is on super tight.

 

[ShadowsPapa]

Do we think this is an acceptable mod for a post-2021 JL/JT? No washers, second cable is for the winch, nut is on super tight.

Yes

 

[remlemasi]

Yes

Thanks, just wanted to make sure it’s secure enough, especially since the stud is narrower than the lugs and only half the threads are making contact.

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