Trying to bypass auxiliary battery not working. Help!

[Oasis Supernova]

So I'm trying to bypass the auxiliary battery like the title says. 2020 Jeep Gladiator sport. I removed fuse 42. I also removed the negative wire on the tall stud with bigger nut. When I do this my jeep refuses to start. I'm doing this because one of my batteries is dead and jeep wouldn't start the other morning. When I put the black cable back on after charging battery it starts. While running and removing the negative wire it starts to bog down, and try and die. Any help would be greatly appreciated.

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[KevinC]

When you say "one" of my batteries is dead...which one is dead? How do you know your main isn't dead? Disconnecting the larger negative cable results in your Jeep not starting. What happens when you disconnect the smaller negative? The Gladiator changed the negative cable orientation in 2021 I believe. You may want to go back to battery forum and search for the year you have.

 

[Lost1wing]

One of those cables at you main negative is the main ground that goes to the fender ground next to the battery. That would be a no start for sure. If you indeed removed the correct cable that goes to the Aux negative, your main battery is likely your problem.

You need a VOM and a AGM battery charger, or you can guess at the problem and try different things and possibly make things worse. You can also take advice from this forum, but without knowing what your battery state is, everyone here is guessing too.

With a VOM, you can tell what cable is what at you main negative. You can tell what the voltage is of each battery once disconnected at the main.

 

[Oasis Supernova]

I'm thinking it's my main thats dead. I tried this again with removing the auxiliary negative and applying a battery charger while running and it didn't bog down. I think the main battery is too far gone to keep continuous power while running without a charger. It's definitely a 2020 bought it when they first came out. Still original batteries.

 

[Commodus]

I'm thinking it's my main thats dead. I tried this again with removing the auxiliary negative and applying a battery charger while running and it didn't bog down. I think the main battery is too far gone to keep continuous power while running without a charger. It's definitely a 2020 bought it when they first came out. Still original batteries.

After you get your batteries sorted out you have to check your fuse bar that sits under the fuse box lid on the engine side. You may have blown one of the links if you tried pulling the negative cable while running

 

[Oasis Supernova]

Ugh. I hate vehicles. I did notice while having the auxiliary negative off, and the battery charger on the main battery everything ran normal.

 

[Lost1wing]

Either replace both batteries at the same time or delete the aux and replace the main. Just because sure to charge both batteries with an AGM charger. Your batteries should be disconnected long enough to reset the IBS, but just in case you are quick you can disconnect the IBS while doing the swap.

Big caution on keeping the cables isolated as someone else has mentions.

 

[DrewsJT]

So I'm trying to bypass the auxiliary battery like the title says. 2020 Jeep Gladiator sport. I removed fuse 42. I also removed the negative wire on the tall stud with bigger nut. When I do this my jeep refuses to start. I'm doing this because one of my batteries is dead and jeep wouldn't start the other morning. When I put the black cable back on after charging battery it starts. While running and removing the negative wire it starts to bog down, and try and die. Any help would be greatly appreciated.

I just this morning went to do a battery test on both batteries.
They tried the auxiliary disconnect.
My 22 the large stud was the main ground and that 10 mm was the auxiliary. I had to disconnect both and place the wire from the large stud onto the 10mm for it to start. The auxiliary had a big square lug that the main was bolted to.
Kinda counterintuitive imo

 

[Oasis Supernova]

Mine was the opposite. Easier to figure out and trace wires when the battery is out. Everything worked like a charm once I got a new mIn battery.

 

[DrewsJT]

Mine was the opposite. Easier to figure out and trace wires when the battery is out. Everything worked like a charm once I got a new mIn battery.

I agree. Seemed odd to attach the main ground to the auxiliary terminal but when I removed the large 13mm, I had no power.

 

[Gee Man]

When you say "one" of my batteries is dead...which one is dead? How do you know your main isn't dead? Disconnecting the larger negative cable results in your Jeep not starting. What happens when you disconnect the smaller negative? The Gladiator changed the negative cable orientation in 2021 I believe. You may want to go back to battery forum and search for the year you have.

REMOVE THE GROUND WIRE.

 

[KevinC]

REMOVE THE GROUND WIRE.

Huh? Why you yelling at me? My batteries work.

 

[Oasis Supernova]

Huh? Why you yelling at me? My batteries work.

Lol

 

[Blade1668]

Lol

So have you got this sorted out yet? After I had a battery failure and tried to do the same thing it was already to late for the fuse bar noted early on. The 150 amp fuse next to B+ was blown. After dealership tow replacement and cleared codes they replaced it but connected up differently to the fuse bar. Mine is a 2020 Sport S.

 

[Oasis Supernova]

Everything turned out great on mine after getting a new battery. Auxiliary is disconnected, and no problems.

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